Many rivers around the world naturally run beneath the ground, but others have been forced underground due to flooding, pollution, location, and diseases. Some of these rivers were dammed, covered, and diverted through concrete or brick sewage systems, and cities were built over top.

These once-thriving rivers fell victim to the concrete jungle, but some have successfully been daylighted in recent years. Many people don’t even realize that rivers are flowing beneath their cities.

10 Neglinnaya River
Moscow

Flowing under Red Square, Alexandrovsky Sad, and the Metropol Hotel in Moscow is the Neglinnaya River, also known as Neglinka, Neglinna, and Neglimna. The natural river once flowed openly from northern Moscow to the south across the center of the city.

The river was first used as a moat around the Kremlin to help stop foreign invasions, but it was mostly unsuccessful. People living in the area began to see frequent flooding, and the Muscovites knew that something needed to be done with the river.

In 1792, they constructed a new canal parallel to the Neglinnaya River and diverted the water into the new tunnel. The old riverbed was covered by the builders. After the Fire of Moscow in 1812, the canal became so polluted that it was covered with a vault.

There have been several tunnels added, built, or expanded since the first one was constructed. The river now discharges into the Moskva River through two tunnels near Bolshoy Kamenny Bridge and Bolshoy Moskvoretsky Bridge.^[1]

9 The Senne
Brussels

One of the defining moments in the history of Brussels was the covering of the Senne. The city was built along the Senne, and it crossed Brussels from one end to the other.

Many industries began to move into the city, and the river quickly turned into an open-air sewer that overflowed during most rains. The water became heavily polluted and produced a strong foul odor across Brussels. Constant flooding and a cholera epidemic were the main reasons for the Senne’s demise.^[2]

After city officials decided that it was time to vault the river, the construction lasted only four years. The Senne was replaced by canals, and buildings were soon built over the buried river. The underground waterway was later diverted, and by 1976, the former water tunnels were converted for use by the Brussels subway system.

In 2000, the first modern wastewater treatment plant came into service to help the Senne regain its original role. A second treatment plant was up and running by 2007.

8 The River Fleet
London

Snaking under the streets of Holborn, King’s Cross, and Camden is the River Fleet, London’s lost river. It is the largest of London’s mysterious lost subterranean rivers.

It was called the “hollow stream” by the Anglo-Saxons. Even before that, it was a major river used by the Romans. They relied on it as a major water supply because many butchers, brewers, and mills needed the water.

As the years passed, London developed into a large industrial area and the clean water started disappearing. The river was heavily polluted and began to stink.^[3]

After the Great Fire of London in 1666, there was a proposal to widen the river to act as a firebreak. The idea was rejected. Instead, the River Fleet was converted into a canal, which was unpopular and unused.

It was eventually covered and incorporated into the sewer system. Locals claim that the waters can be heard flowing through Clerkenwell, and the Fleet waters can be seen discharging into the Thames on certain days.

7 Tibbetts Brook
New York City

Just north of the Bronx is the beginning of Tibbetts Brook, and it flows into a small lake at Van Cortlandt Park. More of a stream than a river, the water then disappears underground and flows through a brick sewer. However, it is considered one of the underground rivers that New York City is working to daylight.

The Native Americans once inhabited this region and used the stream for water and food. They named the brook Mosholu (“smooth or small stones”) because it flowed over these types of stones.

In 1691, Jacobus Van Cortlandt dammed the portion that flowed through his property, creating the Van Cortlandt Lake. Water from the lake was used to power a gristmill and sawmill.

Years later, the city acquired the property that is now known as Van Cortlandt Park. There are currently efforts underway to daylight Tibbetts Brook. The project would help bring the stream back to the surface between the lake and Harlem River instead of having it run through a sewer.^[4]

6 Park River
Hartford, Connecticut

Hundreds of years ago, a river flowed through Hartford, Connecticut. We’re not talking about the Connecticut River but instead the smaller and less popular Park River.

It was first used as a source for mills and other factories, but it soon turned into an industrial and human waste dumping ground. It is also commonly known as “Hog River” because of the several farms with pigs that lined the river.

Due to the massive pollution of Park River, the local government decided to bury the river beneath the city with concrete tunnels and drainage ditches. Begun in 1940, it was one of the largest, most expensive projects ever undertaken by the Army Corps of Engineers.^[5]

It took four decades and more than $100 million to complete, but the river now runs under Hartford. The upper part of Park River is exposed and open to the public, but the underground section is off-limits to visitors trying to catch a glimpse of the lost river.

5 Wien River
Vienna

The Wien is a river in Austria that flows through the city of Vienna. After devastating floods that were often accompanied by cholera, concrete was poured to act as the riverbeds.

The water was diverted underground and is now mostly covered by the city and integrated into the sewer system. In 2013, the City of Vienna approved plans that would build three separate terraces along the river.^[6]

Stadtpark, Vienna’s first public park, is located on the bank of the Wien River and features beautiful landscapes, artistic sculptures, and shady pathways.

4 River Bievre
Paris

The Bievre is a 36-kilometer (22 mi) river that flows into the Seine in Paris. It has long been covered over and diverted down tunnels into the sewer system once it reaches the city.

The river once flowed into the Seine within the city, but it was later diverted to cascade into it further downriver. Several industries along the water created pollution that caused the covering and redirection of the Bievre.^[7]

Restoring the Bievre has been a topic of discussion for many years, and several organizations have promoted this work. Many hope that the daylighting of the river will occur in the near future to help create a new habitat for plants and animals. They also believe that exposing the buried river will reduce flood risks and forge new “green corridors” through urban areas.

3 Sunswick Creek
New York City

A freshwater stream flowing through Queens is known as Sunswick Creek. Scholars believe that the name may have come from a Native American word meaning “woman chief.” In the 1800s, Sunswick Creek and its marshy surroundings became polluted from sewage and industrial discharge. By 1879, the marshes were drained and the creek was either filled in or incorporated into the sewage system.

The burial process of Sunswick Creek apparently occurred in multiple phases. Urban explorers have captured several photographs of the large sewer-like pipes through which the water now flows. The creek still runs below modern streets. If you are standing near the former Somer Piano Factory building on Vernon near Socrates Sculpture Garden, you can hear the creek roaring!^[8]

2 The Cheonggyecheon
Seoul

The restoration of the Cheonggyecheon proved that a green oasis can be placed inside a concrete jungle. It was once the main river flowing through Seoul, and many houses were built along the stream. Trash, waste, and other pollution eventually blanketed the waters and became an eyesore for the city. The Cheonggyecheon was then covered with concrete as an elevated highway took its place.

Around the year 2000, government leaders promised to remove the freeway and restore the Cheonggyecheon. The traffic-filled elevated freeway has now been transformed into a 5.8-kilometer-long (3.6 mi) stream corridor filled with natural beauty.^[9]

The restoration project provides flood protection for up to a 200-year flood event. It also contributed to a 15.1 percent increase in bus ridership, a 3.3 percent rise in subway ridership, and a 30–50 percent surge in the price of land for properties within 50 meters (164 ft) of the restoration.

The Cheonggyecheon restoration project, which attracts 64,000 visitors daily (including about 1,400 foreign tourists), is known as one of the greatest daylightings of a river in history.

1 Bradford Beck River
England

Once a clear and open river, Bradford Beck now flows through beautiful, arched foundations beneath Bradford, England. The river system was once used to power corn mills and fulling mills, and Bradford grew to be the center of the world’s wool industry.

By 1840, raw sewage and industrial discharge filled the beck. People in the area continued to drink the water and eventually saw outbreaks of typhoid and cholera. Life expectancy in Bradford was one of the lowest in the country.

By 1870, Bradford Beck was placed in a culvert and built over, hiding the river from clear view. Water quality has greatly improved since the river was forced underground, but there has been little improvement to the physical character of the river.^[10]

Daylighting the beck will not be an easy task due to the many buildings under which the river runs. There are 15 plaques located across the city that mark the route of the hidden river. Each plaque carries a couplet of a poem about the river. The first plaque is located alongside Bradford Live, and the final plaque can be found across the road from the Broadway.

I’m just another bearded guy trying to write my way through life. www.MDavidScott.com

In cities the majority of space is off-limits. Parks and streets may account for up to half the total area, but when you factor in the vertical axis—the floors inside buildings (many of them empty)—you get a different picture. And that’s just the space that we know about. Often there’s a lot more underground.

In order of size, here are 10 of the most spectacular subterranean sights you’re forbidden from seeing or, in some cases, even from knowing they exist.

10. Mumbai’s imperial underworld

When an occupying force takes over your country, it tends to cut you out of the loop. Hence, whenever Indian construction workers find structures under cities once controlled by the British, they don’t know what they were built for. The vault beneath Kolkata’s National Library, for instance, might have been anything from a treasury to a torture chamber—or, as it eventually turned out, just part of the building’s foundations. 

Mumbai has a veritable underworld of abandoned imperial structures, from the 13-room bunker under Raj Bhavan (the seat of city government) to the kilometer-long tunnel under the old General Post Office.

Another mystery was unearthed as recently as 2022: a 200-meter tunnel under Mumbai’s JJ Hospital, a building whose foundations were laid by the British governor. Appearing on no maps, it was only discovered in a water leak survey. And it was blocked at one end so it wasn’t clear where it once led. While it’s thought to have been to a neighboring hospital, it remains something of a mystery for now—as does the number of underground structures that remain to be found in Mumbai.

9. LA’s prohibition partyways

While the rest of America endured its first War on Drugs—the doomed-to-fail prohibition of alcohol—the mayor of LA kept the hooch flowing through a network of underground service tunnels. These were also the routes by which the flappers and dapper gents of the city’s roaring party scene got from one bar to the next without hassle. Originally built as service tunnels, and for a subway to ease traffic on the surface, they ran for more than 17 kilometers connecting basements converted to speakeasies.

One such bar was the King Eddy Saloon. Established almost 20 years before Prohibition, it moved underground to survive—transforming its above-ground premises into a piano store. Others include the Edison, in the basement of the city’s first privately owned power plant, and Cole’s, under the Pacific Electric building. Patrons of all these establishments, armed with a password, stumbled around wasted, completely unseen by police and paparazzi.

Despite their historic significance, the passages and basements are now closed to the public and even largely unmapped. Many are flooded and crumbling. Just like in the old days, however, those in the know can find their way in—as evidenced by the tunnels’ graffiti. According to Atlas Obscura, there’s an “easy-to-miss elevator” on Temple Street. And there’s also, apparently, an entrance off the subway from Downtown to Hollywood.

8. Havana’s secret chambers

In the early 1990s, the Cuban government was reported to have secretly built more than 33 kilometers of tunnels under Havana. These were to serve as bomb shelters amid escalating threats of invasion by the United States.

Known as the Popular Tunnels, they were manually dug by hundreds of laborers and their entrances carefully hidden. But these were just the latest of a long tradition of tunneling under Cuba. All the way back in 1929, the New York Times reported on the discovery of five secret chambers under Havana’s City Hall.

7. Tokyo’s hidden network

From rivers and forgotten canals to the world’s largest sewer system, there’s plenty below Tokyo that we know about. But there may a lot more. When journalist Shun Akiba compared an old map to a new one, he found differences suggesting not only unknown tunnels but an effort to cover them up. Whereas the new map showed subway tunnels crossing in Nagata-cho, for instance, close to the National Diet building (the seat of government), the old map showed them as parallel. Shun also found evidence of an underground complex between the National Diet and the prime minister’s residence. He also remarked on the mysterious tunnels leading off the Ginza Line.

Official enquiries got him nowhere, he said, lips were “zipped tight” despite his respectable professional background as a war correspondent for Asahi TV. From what he’s seen, Shun believes there must be close to 2,000 km of tunnels beneath the city—eight times the stated 250 km. And many of them (the Namboku, Hanzomon, and O-Edo lines, for instance) were built long before their conversion for trains. That the Chiyoda line platform at Kokkai-gijidomae, the National Diet station, is the deepest in Tokyo, suggests it was built as a bomb shelter. Yet old blueprints show another level even deeper. There’s also the mystery of the Yurakucho line, which, with its high ceilings and military facilities on route, is rumored to be a secret road used by the military. Although the network dates back to World War Two and the Cold War era, the continued silence from officials suggests they may still be in use.

6. Washington’s whack-a-mole hidey-holes

The two main parties of the military-industrial regime based out of Washington have plenty in common, but one thing stands out: they’re both afraid of the public. Hence their underground tunnels to get from one building to another—tunnels they’re advised to make use of. Some of these famously served as evacuation routes during the 2021 Capitol siege, but they are in fact used every day just to avoid going outside.

According to The Drive, there’s “a labyrinth of at least 19 underground passages on Capitol Hill”,  not only for people but vehicles as well. The oldest date back to the 1800s, when they were built for water and ventilation, as well as to transport books by electrical conveyor belt between the Capitol and Library of Congress. When the Russell building was finished in the early 1900s, it came complete with a subway car system in a tunnel so fortified that it was, many years later, designated as a fallout shelter. As other buildings followed, the tunnel network grew. And nowadays the Cannon Tunnel, between the Cannon building and the Capitol, is more like an underground town with “a shoe repair store, post office, credit union, and cafeteria.”

Among the most recent major works was a 54,000-square-meter expansion of the Capitol building’s underground complex. This added three underground stories to the existing network with links to nearby offices and a 305-meter tunnel to the northwest, officially built for screening garbage trucks for explosives. That was in the 2000s, amid growing secrecy regarding Washington’s underworld—not to mention the tunnels and bunkers that lie deep under the White House.

5. Moscow’s many secrets

The largest of Europe’s old fortresses, the Kremlin sits atop a labyrinth of secret passageways. There’s the haunted Neglinnaya river tunnel, for example, the Syani stone mines where the city sourced limestone for construction, and, although it’s yet to be found, the library of Ivan the Terrible. Excavations for the latter have all turned up nothing but tunnels: “endless tunnels, buried, stoned in, heading in unknown directions”. While the search was called off, however—in part because of damage to foundations—the library’s still thought to be down there, along with its priceless collection. 

What has been found are the dungeons under two of the Kremlin’s towers, in one of which Ivan the Terrible imprisoned Prince Andrei Khovansky. Those condemned to torture were kept gagged and chained to the wall, allowed to speak only when addressed by their captors. The nearby dungeons of the Cathedral of the Archangel kept prisoners of the church, people who owed it money, on painful posts known as “penitence chairs”. Just next door are the cathedral’s stone treasuries, built to withstand both fires and theft.

Much more recently constructed was the Metro-2, a parallel subway system built, in secret, around the same time as the main one. Intended to evacuate the government, it runs as deep as 250 meters in places. And not much is known about it, either, except that it does exist; Moscow’s first post-Soviet mayor confirmed that in 2006. 

4. New York’s abandoned subways

There are numerous disused rail tunnels under New York City. Track 61 beneath the Waldorf Astoria is among the most storied, having once carried presidents and generals like Roosevelt and MacArthur. In 2003, it was even considered as an escape route for George Bush and his lackeys. It has also hosted a fashion show and an Andy Warhol event. Other subways were constructed for the mail, such as the Farley-Morgan Postal Tunnel under 9th Avenue. Although it’s sealed off now, it was briefly used in 2004 to sneak guests between venues for the Republican National Convention. 

The Atlantic Avenue Tunnel under Brooklyn, meanwhile, has been abandoned since 1861—less than 20 years after it was built in 1844. It’s the oldest subway in the world and was only briefly reopened in 1918 to look for Germans.

But there’s a lot more under New York besides subways. One of the most interesting and unique tunnels is the 66-kilometer underground aqueduct between Bryant Park and the Croton River in Westchester. Disused since the 1950s, this “perfectly preserved” tunnel—the 1842 Croton Aqueduct—once carried millions of gallons of water to the city. It was all stored at the Distributing Reservoir in Bryant Park, a vast, 16,000-square-meter structure resembling an ancient Egyptian temple. It was actually thanks to this place, the solution to Manhattan’s disgusting sanitation problems, that the city is still there today.

3. Rome’s ancient quarries

So extensive are the ancient tunnels and quarries under Rome, dating back to the founding of the city, that it’s common for sinkholes to form and for buildings on the surface to collapse. It was only in 2013 that geologists mapped the network, amid an increasing number of such incidents. There were 44 collapses in 2011, followed by 77 in 2012, and 83 by December 2013. Residents have usually patched up the damage themselves using big plastic bags of cement.

The original ancient Roman tunnelers actually tried to guard against this happening (in their own day, at least) by keeping the passageways narrow. This ensured the surface was still largely supported. Over time, however, the exposed rock has weathered. Not only that but later generations have widened the original tunnels and kept building more.

Although they’re not open to the public, they’ve been used by Romans down the ages as catacombs, sewers, and mushroom farms, as well as shelters in the Second World War.

2. London’s tunnels of intrigue

With its dungeons, crypts, and catacombs, 13 underground rivers, and plague pits from the mid-1300s, the history of London lies just below the surface. More recently, however, officials confirmed what urban explorers have known for decades: the existence of a sprawling network of underground tunnels connecting government buildings with secret chambers. According to the Land Registry in 2017, most of them were built by the Post Office, British Telecom, and the Ministry of Defence.

One of the more interesting parts of the network, the Postmaster General’s tunnel, runs from the East End of London to what used to be the War Office at 57 Whitehall (now an overpriced hotel). At various points along the way, elevator shafts connect it to government departments and telephone exchanges. Deep under High Holborn Street, not far from Whitehall, one such exchange was built as a government bomb shelter, complete with a restaurant, games rooms, and two bars (one for tea and one for booze).

The tunnels have, officially, been out of use since the Cold War era, but they were never opened up to the public. While those who’ve managed to sneak down there do say it’s like a time capsule, untouched in decades, they’ve only seen parts. Access to the deeper levels is suspiciously bricked off, the lights are kept on, and trespassers are disproportionately punished.

1. Beijing’s underground city

Built to hold 40% of citizens in the event of a war with Russia, Beijing’s dixia cheng (“underground city”) covers a remarkable 85 square kilometers—all hand-dug by citizens during the Cold War. It’s also known as the “underground Great Wall of China”, for its massive scale. But you’re not allowed to see it. 

The official guided tour takes in only a small, looping, and commercialized fraction of the whole. The rest of the corridors, tunnels and bunkers are said to be inhabited by up to one million homeless—the so-called Rat Tribe (who presumably stand to inherit the Earth). But that sounds too good to be true. While some of dixia cheng has been converted to low-cost, sub-standard apartments, it’s hard to imagine the CCP leaving all of it to poor people and tramps when there are hundreds of more selfish uses. With 90 entrances across the city, for example, its potential for “disappearing” citizens is obvious.

In any case, whatever’s really down there, it was built for long-term habitation, with storage for grain and space for mushroom farming, as well as restaurants, barber shops, a cinema, classrooms and anything else to help persuade citizens that things were still normal.

The Earth’s surface holds many wonders great and small, natural and man-made. A different, though no less mesmerizing, world exists below. Human beings, while certainly not optimized for these environments, enter them regularly. Tourists visit caves, commuters shoot through subway tunnels, and miners across the world work underground as a matter of course. By and large, such forays into the ground do not last, and spelunkers, miners, and commuters emerge into the light and fresh air of the world above.

Sometimes, however, that’s not so easy. Sometimes, calamity leaves one or more unfortunate souls trapped underground, unable to reach the surface without help. In these dire situations, the entombed are left with few options but to hope for rescue. Some get it; others die in absolute darkness, feeling only their own fear and the indifferent, immutable rock around them.

10 Sago Mine Disaster

January 2, 2006, was supposed to be an unremarkable morning for the workers at Sago Mine, nestled in the heart of West Virginia. New Year’s was over, and it was time for work. Ultimately, the reluctant return to the daily grind was to be anything but.

At around 6:30 AM, an explosion rocked the mine as workers were entering. A resultant cave-in trapped 13 miners inside. Those lucky enough to have found themselves on the other side of the cave-in immediately attempted to dig their coworkers out, but too much carbon monoxide had seeped into the air for them to do so. The trapped miners were equipped with emergency oxygen packs, but to add to their misfortune, not all of them worked.

The miners remained trapped as rescuers attempted to reach them. Try as they might, there was no escaping the fumes. There was little else for them to do but pray and write letters to their loved ones. One by one, they lost consciousness.^[1]

In a pattern that will be repeated on this list, the rescue operation above attracted a media circus. Over 40 hours after the explosion, the miners were found. All but one had died. The lone survivor, Randal McCloy, was in critical condition and would not regain consciousness for days. In a cruel twist of fate, miscommunication initially led to reports that 12 miners had survived. Within a few hours, that egregious error had been corrected.

The cause of the January 2 explosion has been a subject of contention. International Coal Group, which owned Sago Mine, as well as two West Virginia state agencies declared that a lightning strike probably ignited methane in the mine. Meanwhile, the United Mine Workers attributed the disaster to friction between rocks and/or metal supports. Sparks from equipment being restarted due to work resuming after the holidays have also been blamed. Sago Mine was reopened a few months later but was eventually sealed by International Coal Group.

9 Alpazat Caverns Rescue

In March 2004, six British soldiers, members of the Combined Services Caving Association, were inside Alpazat caverns, located in the Mexican state of Puebla. Their expedition was intended to last 36 hours but became a good deal longer when flash flooding prevented them from leaving the cave. The men found themselves trapped on a 4.6-meter (15 ft) ledge above a raging underground river.^[2]

Luckily, the cavers were prepared for such a contingency. They had enough food to last for days, plenty of light sources, dry clothing, and the river for “hygienic needs.” Six more members of their party were outside the cave and able to contact rescuers. Eight days later, the men were led out, one by one, by cave divers, a process which took six hours. They emerged into the midst of a war of words between Mexico and the UK.

What was the problem? Well, suspicions arose when it came to light that the men had entered Mexico with only tourist visas and hadn’t notified Mexican authorities of the caving expedition. The cavers also refused help from Mexico and elected to wait for two British cave diving experts to arrive at Alpazat caverns, which was seen as a slight. (In the end, those two divers still worked with five local cavers and about 40 Mexican soldiers to rescue the trapped men.) Rumors flew about the group’s activities, including that they were prospecting for uranium. One of the cavers outside, awaiting the rescue of his teammates, said of the trip: “It’s an official military expedition to support adventurous training.” The whole awkward affair was described as a “diplomatic dog’s breakfast.” The rescued men were fine.

8 Julen Rosello

Tragedy struck on January 13, 2019, in Totalan, a village near Malaga in Southern Spain. That day, two-year-old Julen Rosello (also named as “Julen Rosello Garcia” and “Julen Rosello Jimenez” in various reports) was with his parents out in the countryside when he fell into an unmarked borehole. Julen’s father saw him nearing the hole and ran to stop him, but it was too late. Though the well’s opening was reportedly covered by rocks, tiny Julen fell in. His father could hear Julen’s cries only when he first reached the mouth of the 110-meter-deep (361 ft) shaft and no more afterward.

Rescue efforts began immediately. Complicating matters was the fact that the borehole was only 25 centimeters (10 in) wide. Around 300 people were involved in the process of digging a parallel shaft to reach Julen, a task which occasionally necessitated explosives. The operation was described as months’ worth of excavation being carried out in only days. Sadly, it was all for naught. During the early morning hours of January 26, 13 days after he fell in, Julen’s body was found 71 meters (233 ft) down, lying upon compacted earth. It is believed that he fell feet-first and died on impact.^[3]

Strangely, there had also been plugs of compacted earth above Julen, something which hindered rescuers. It was surmised that his fall may have dislodged chunks from the side of the failed well, which subsequently covered Julen. The businessman who had dug the hole claimed to have sealed it afterward but said that it must have come open again somehow.

7 Yorkshire Rescue Attempt

On June 1, 2019, Harry Hesketh, age 74, was exploring a cave on Fountains Fell, a mountain in Yorkshire. At around 11:30 AM, the experienced caver fell down at 6-meter (20 ft) drop and broke his leg. His two friends immediately went to summon help. A total of 94 people worked tirelessly both above and below the surface to save Mr. Hesketh.^[4]

As is so often the case in these situations, that was easier said than done. The passages were narrow and unmapped. Nevertheless, rescuers managed to reach Harry with medical supplies and began to monitor his condition and keep him warm. It was clear that Harry would have to be immobilized to be taken out of the cave.

Workers tried to widen the passage as quickly as they good in order to save the trapped caver, but time was not on his (or their) side. Around 12 hours after his fall, Harry Hesketh died. It took roughly five and a half more hours to remove his body from the cave.

6 Quecreek Mine Rescue

On the evening of July 24, 2002, 18 miners were working second shift at the Quecreek Mine in Somerset County, Pennsylvania. Work was being performed near the old Saxman Mine, which was no longer in use. It was believed that about 90 meters (300 ft) of rock still separated the miners from the disused mine. This was not the case.

At around 9:00 PM, the miners broke through into Saxman, which had filled with groundwater. Millions of gallons of water rushed into Quecreek Mine as the workers ran for their lives. Nine men could not escape. They found themselves stuck 73 meters (240 ft) below the surface in a chamber which was a mere 1.2 meters (4 ft) high.^[5]

A rescue operation soon began. By midnight, calls had gone out for a drill capable of boring a hole large enough to retrieve the trapped miners. One was found in Clarksburg, West Virginia. In the meantime, rescuers spent the early morning hours of July 25 drilling a 15-centimeter-wide (6 in) hole down to where the miners were trapped. After the drill broke through, they heard tapping, indicating that the men were alive. Warm compressed air was pumped through the narrow shaft to keep the miners warm and hopefully keep the water at bay.

That afternoon, the so-called “super drill” arrived under police escort. The drilling of a rescue shaft 76 centimeters (30 in) wide began that evening and was initially expected to take 18 hours. However, mere hours into July 26, the drill’s bit broke roughly 30 meters (100 ft) down. A replacement bit was rushed to the site via helicopter, with a backup shaft being drilled nearby in the meantime. By 8:00 PM on July 26, drilling of the primary shaft had resumed. Nevertheless, worry had settled in among the rescue crew, who hadn’t heard any tapping from the miners since around noon the previous day.

Finally, after 10:00 PM on July 27, the super drill made it to the miners’ chamber. Food and a telephone were soon sent underground. Not long after that, rescue workers began to smile and give thumbs-ups. The men were alive, all of them. The crew leader, who had begun to experience chest pains, was brought up first. Then the rest came over the next few hours. The rescue was a much-needed happy ending for a community living a stone’s throw away from the crash site of Flight 93, 9/11 having happened less than a year earlier.

5 Floyd Collins

Floyd Collins stands as the most famous casualty of the Cave Wars, a period during the early 20th century in Kentucky when owners of various caves fiercely competed for tourist dollars. One such cave was Crystal Cave, owned by the Collins family. Unfortunately, its remote location meant that few tourists came to it. Floyd Collins sought to claim a cave in a better spot. He knew of one, called Sand Cave, which was conveniently located close to a road. This cave hadn’t been explored, and Collins made a deal with its owner to share half the profits if the cave turned out to be a worthy tourist attraction.

On January 30, 1925, Floyd entered Sand Cave, carrying only a kerosene lamp for light. The cave soon proved to be challenging, with Collins worming his way through a narrow, winding passage, inching ever deeper into the ground. Finally, the passage began to widen, but it was at this point that Floyd’s lamp began to flicker, leaving him with no choice but to return to the surface. As he made his way up, he dislodged a 12-kilogram (27 lb) rock that pinned his left foot. Floyd was completely unable to free himself, his arms stuck at his sides. All he could do was yell for help.^[6]

He was finally found a day later by his brother, Homer. However, there was no extracting Floyd from above. Days passed, and the scene became a carnival, with thousands of gawkers showing up. During the chaos, a young reporter named William Burke “Skeets” Miller, a rather small man, repeatedly crawled down into Sand Cave to interview Floyd as well as bring him food and an electric light bulb for warmth. Miller’s interviews later won him a Pulitzer Prize.

After a cave-in blocked access to Floyd, workers began to dig a shaft to get him out. Finally, 18 days after he became trapped, they reached Floyd, but it was far too late. He had been dead for several days. The crowds dispersed, and a funeral was held outside the cave. This, however, was not the end for poor Floyd.

Homer, with the help of friends, dug his own shaft and managed to finally recover Floyd’s body on April 23. Floyd was buried on the family farm. In 1927, Floyd’s father sold the family’s property, including Crystal Cave, and the new owner displayed Floyd’s remains in a glass-topped coffin in the cave. Then, in March 1929, Floyd’s body was stolen. It is said that the body was found missing the left leg which had been pinned four years before. After this, Floyd’s remains were still kept in Crystal Cave, albeit now in a chained coffin in a remote part of the cavern. In 1961, the National Park Service bought and closed Crystal Cave. Finally, in 1989, Floyd’s remains were removed from the cave and interred in a cemetery.

4 69 Days Underground

On August 5, 2010, a cave-in occurred at the San Jose copper and gold mine near Copiapo, Chile. As a result, 33 workers found themselves trapped 700 meters (2,300 ft) below the surface. Matters were further complicated on August 7, when another collapse cut off access to ventilation shafts. Rescuers topside began drilling listening holes in an attempt to discern the workers’ status. These efforts were hampered by outdated maps of the mine.

Down below, the miners were in a bad situation. They were stuck in hot, humid air at a temperature of 35 degrees Celsius (95 °F), which led some to develop fungal infections as well as respiratory and eye problems. They only had enough food to last two days, so they took one meal (two spoonfuls of tuna, half a glass of milk, and half a cookie) every other day. They were able to obtain water from radiators and a spring. They had to subsist this way for 17 days.^[7]

On August 22, rescue workers up above finally detected tapping on one of their probes. When they pulled it up, there was a note indicating that everyone was alive. From this point forward, it was possible to send the men food, water, and supplies through the borehole. Additionally, movies and music were sent down, and a cable allowed the trapped workers to directly communicate with those above, including their families. Actual rescue, however, was still far off.

The 33 men developed a routine over the subsequent days. They formed three teams which worked, played, or slept in eight-hour intervals. Work involved helping the rescuers in any way they could as well as checking on the well-being of the other miners. Play entailed watching movies or playing cards, dominoes, or dice games. The men also exercised by simply running up and down the tunnels.

Meanwhile, three separate drilling rigs had been brought to the site, and three shafts were being dug. On October 9, one of the three broke through into a chamber the miners had access to. Then came the task of lining the rescue shaft with metal in preparation for the extractions. Finally, just after midnight on October 13, the first rescued miner saw the sky for the first time in months. By the end of the day, the last man had been pulled out. All 33 had survived a total of 69 days underground.

3 Baby Jessica

On the morning of October 14, 1987, 18-month old Jessica McClure, soon to be known to the world as Baby Jessica, was playing among other children in the backyard of the Midland, Texas, daycare run by her aunt. Jessica’s mother, Cissy, was watching the children but briefly stepped inside to answer the phone. During that time, Jessica fell into a 20-centimeter-wide (8 in) well and became trapped 6.7 meters (22 ft) below. As with the case of Julen Rosello above, the well had been supposedly covered with a rock to prevent exactly this sort of calamity, but it nevertheless happened.

Alerted by the screams of the other children, a frantic Cissy called the police. The narrowness of the well and the hardness of the earth around it made rescue a challenge, to say the least. Rescuers brought in a machine normally used to dig holes for telephone poles and used it to excavate a 76-centimeter (30 in) hole (29 ft) into the ground. Then came the task of drilling horizontally to reach Jessica.

As this was happening, oxygen was pumped into the well, and workers did their best to keep communicating with Jessica. Fortunately, she was more than willing to talk, speaking to rescuers or making some sort of sound for most of the operation, though she was not a fan of the noise generated by the jackhammers. A detective working at the scene recalled her singing “Winnie the Pooh.”

During the evening of October 16, Jessica was finally lifted out of the well. She had been stuck underground for 58 hours. The whole rescue had been covered lived by CNN, something relatively uncommon at that time. An iconic photograph of a paramedic carrying Jessica earned the photographer, Scott Shaw, a Pulitzer. Jessica required 15 surgeries over the next few years due to the aftereffects of her time in the well, but she ultimately recovered and has little memory of the event.^[8]

2 Chasnala Disaster

Catastrophe struck on December 27, 1975, at the Chasnala colliery, a coal mine in India. The mine was situated next to an abandoned one, which, predictably, was flooded. Only a barrier of rock and coal protected the operational coal mine from the reservoir of the old one.^[9]

At around 1:30 PM, an explosion damaged that barrier, sending torrents of water and debris into the mine. The initial response was chaotic, with officials reportedly fleeing and the first water pumps that were used being inadequate for the task at hand. Better pumps had to be brought in from the US, Poland, and Russia.

Twenty-six days after the explosion, the first body was finally retrieved. Others were eventually recovered, and many could only be identified by the numbers on their helmets. Plenty were never found. Depending on the source you consult, between 372 and 380 people were in the mine. No one survived. There are rumors that the death toll is actually higher, as there were also 130 contract laborers working that day.

After the tragedy, it was reported that there had been prior warnings that exactly this sort of flood could occur. These warnings were ignored. Today, a memorial known as the Shaheed Smarak stands for the victims.

1 Tham Luang Cave Rescue

On June 23, 2018, 12 members of a local youth soccer team, the Wild Boars, in Thailand’s Chiang Rai Province had just completed practice. The boys, along with their assistant coach, decided to do something they’d done plenty of times before: venture into the nearby Tham Luang cave for to write the names of new team members on a wall, something of a Boars tradition. They bicycled across rain-soaked fields and into the hills, parking their bikes by the cave’s entrance and entering with flashlights for a quick trip.

What they did not consider is that the Tham Luang cave system should only be entered between November and April. During the monsoon season, which typically starts in July, it is an extremely dangerous place. Indeed, the team found themselves facing a flash flood which blocked their exit and forced them deeper underground. They ended up trapped 4 kilometers (2.5 mi) from the cave entrance.

When the boys failed to turn up that evening, it didn’t take long for their parents to figure out where they might have gone. Rescue efforts were promptly underway, involving the police, various rescue teams, volunteers, and the Thai Navy Seals. Even with such a group assembled, finding and saving the team would not be easy. The Navy divers, despite their training, largely had little cave diving experience. On top of that, rain was still a frequent occurrence. Rescue workers did what they could to pump water out of the cave. Others drilled into the mountainside, hoping to find other passages into the cave system. Thermal sensors and drones were also employed to locate the trapped boys. Team members who hadn’t gone into the cave on June 23 were asked about where the boys would usually go. Word of the incident spread around the world, and rescue workers and cave divers from a multitude of countries began to arrive on June 28.

While the world watched above, the 12 boys and their coach remained on their ledge with no food, though potable water dripped from the walls. They used rocks to dig a 5-meter cave of their own, which they would huddle in for warmth. The assistant coach, a former monk, taught them meditation techniques and instructed them to remain still to conserve strength. Time began to lose all meaning for the trapped soccer team.

On July 2, two British cave divers found the team. Elated to see that everyone was alive, the divers left lights and returned to the surface to deliver the good news. A medic and other divers joined the Wild Boars and would stay with them for the remainder of their time in the cave. Despite the team members’ strong desire for some solid food, a doctor mandated that they be kept on a diet of liquid food and vitamin-infused mineral water. Next came the challenge of guiding the 13 through a stretch of submerged cave that would be a challenge for experienced divers. One of the team couldn’t swim. The danger was underscored only a few days later, when Saman Gunan, a former Thai Navy Seal who had volunteered to help, died while returning from delivering air tanks to the boys.

On July 7, the rain let up, but it was decided that the team had to be rescued by July 10, when it was predicted that the cave would be completely flooded. The children were given full face masks and air tanks. They were clipped to divers and also had handles attached to their backs. It has been reported that the boys were heavily sedated so they wouldn’t panic during their trip to the surface. For transportation over a part along the way that wasn’t flooded, the boys were placed in stretchers. Pulleys were used to get them up a steep slope.

One by one, the team members were extracted from the cave over the next three days. By July 10, water levels were indeed rising again. Not long after the last Wild Boar made it to the surface, the three men who had stayed with them underground emerged. Right after that, a pump failed, sending more water into the cave and workers scrambling. Nevertheless, the team was safe.^[10]

Not all tunnels are created equal, especially in Ireland where robbers, explorers, and the elite of society used them to avoid being seen.

Many underground passageways were mere legends before being unearthed in the last century. Others were completely unknown and revealed mysteries that still confound archaeologists and explorers alike.

Which tunnel would you most like to explore?

10 Haunted Tunnels With Really Creepy Backstories

10 When You Gotta Go

In 1985, a gang of bank robbers decided to dig a tunnel to Dublin’s Allied Irish Bank on Dame Street. However, when they came up for air, they found themselves in a ladies’ restroom instead.

The raiders began their underground escapade outside Dublin Castle, which was right beside the city’s main police communications center. They started on the Thursday before Easter and finished the tunnel on Easter Monday.

The gang built a 23-meter (75 ft) tunnel to the bank’s wall. By accidentally entering the restroom, they set off an alarm that warned police of their whereabouts on that long Easter holiday weekend.

After all that trouble, the miscreants were forced to flee without the loot. But even if they had succeeded, it wouldn’t have been that lucrative. Supposedly, the vault only had about $147,000 on hand. Even so, a bank spokesman didn’t believe that the would-be thieves could have pierced the strong room where the money was kept.^[1]

9 Staircase Tunnel Discovered In Cork After 230 Years

Although Spike Island in Cork Harbour was once used as a prison and a defensive structure, it is now a popular tourist attraction. Originally a monastic settlement from the seventh century, the island may have been used as a smugglers’ port in the 1600s, too.

The first artillery fortification was built there in 1779 as a result of the American Revolutionary War. The island was also a port for Britain to supply goods to its forces in North America and the West Indies. In 1790, the first permanent fort was built on Spike Island by the Irish Board of Ordnance.

In August 2020, a tunnel was found after a wall was removed that had blocked the underground passage for decades. The tunnel, which runs under the walls of the fort, is called a “sally port.”

A sally port is a small exit or entryway. It is usually protected with a wall or door that must be circumvented to gain entry and that protects against enemy fire from a great distance. After the door to the tunnel was opened, the staff found a spiral staircase that seemed to float like something out of the Harry Potter stories.

The rediscovered tunnel at Spike island leads out to the moat from the inner fort. A second fort was built on the island in the early 1800s. So it’s likely that the tunnel was blocked off because it was made redundant by the newer construction.^[2]

8 Frescati Stream
Blackrock, Dublin

A tunnel ran under the grounds of the Frescati House where the family of the Trinity College provost lived in 1739. The passageway was built by a later owner—Emily FitzGerald, Duchess of Leinster—to bring seawater to the estate. However, the tunnel is now blocked off. In fact, the exact location of the structure remains a mystery.

In the 20th century, the Frescati House was demolished and the estate was redeveloped into a shopping center. But the Frescati Stream (aka Priory Stream) remains beneath the shopping center car park. From there, the stream visibly passes an apartment complex, ducks under the main road, and ultimately emerges at Blackrock Park.

In earlier times, the course of the stream may have been used by residents to escape raids by the Crown Militia from Dublin Castle.^[3]

7 The Goggins Hill Tunnel
County Cork

Since its closing in 1961, the Goggins Hill (also spelled “Gogginshill”) Tunnel has been Ireland’s longest abandoned tunnel at 828 meters (2,717 ft). Once used as a railway passage, it was carved out by 300 men under the village of Ballinhassig in 1850–51.

The area is overgrown and spooky now, looking very much like a tunnel to the underworld. It has three ventilation shafts. Some sections are hewed from the original rock, while others are lined with bricks to prevent collapses.

For any would-be explorers reading this, be warned that the tunnel is on private land and permission to explore should be asked of the current owner. Trespassers are not welcomed. But with permission, visitors will be allowed entrance.^[4]

6 The Ballymore Tunnel, County Kildare, And Casino Marino, Dublin

In 1852, the Ards estate was inhabited by Lady Isabella Tasca Stewart-Bam, a well-to-do and pious woman. She commissioned the construction of the Ballymore tunnel so that she could walk to church without being seen by the nearby peasants.

In the same vein, a tunnel was built at Casino Marino in Dublin so that servants could travel between the main house and the garden without spoiling the view. In the 18th century, the Casino was a pleasure house for James Caulfeild, 1st Earl of Charlemont. The house had eight tunnels leading from it.

It’s possible that the Earl of Charlemont wanted the tunnels to run all the way to the sea. However, as he ran out of money and died before that happened, their purpose will remain a mystery.^[5]

In 2016, secret tunnels discovered beneath the grounds surrounding Casino Marino were opened to the public. These passageways were used by Irish soldier and revolutionary politician Michael Collins and others to test-fire submachine guns during the Irish War of Independence in the early 1900s.

Top 10 Ingenious Features Of The Cu Chi Tunnels

5 1,000-Year-Old Souterrain Discovered In County Cork

In 2015, workers discovered an underground passageway in the Caha Mountains in County Cork that had been dug through solid rock about 1,000 years ago. This passage is called a “souterrain,” which comes from the French word sous-terrain meaning “underground passageway.”

Archaeologists believe that the idea of a souterrain was brought to Ireland from Gaul in the late Iron Age. Souterrains are associated with settlements and usually found near ringforts.

The workers discovered the tunnel while excavating to widen a tourist road in Bonane. The Caha Mountains in Cork stirred little archaeological interest until then, although they were known to have traces of Neolithic settlements.^[6]

4 Sinkhole In Dublin Reveals Brothel Tunnel For Politicians

In 2015, a sinkhole opened up in one of Dublin’s main streets. Dame Street leads toward Trinity College Dublin and up to Christ Church Cathedral. The 1.8-meter-deep (6 ft) hole collapsed into an old cellar under the road.

According to historian Gerry Cooley, Irish politicians were believed to have sneaked through a tunnel in the 19th century to access brothels. This cellar may be a piece of that tunnel. It was probably used until the building for the Irish Parliament House became the Bank of Ireland in College Green after the Act of Union in 1800.^[7]

3 Underground Jail Cells
County Meath

A secondary school in Trim, County Meath, was being renovated when jail cells were unearthed in underground tunnels. The cells were found intact after a wall was pulled down under the school.

The school had been built near the site of the old Trim Gaol (jail) that was demolished in the 1950s. Initially, the industrial school was set up to prevent pauper children from going to the workhouses by educating them in a trade instead.

Some strange deaths are associated with the site. In 1912, a teacher was murdered in the schoolyard by boys with sticks and brushes. Forty years later, two men died in a fall when the jail was destroyed. The men were placing explosives on the third floor to demolish the building when a wall came down on top of them and sent them plunging to the basement.^[8]

2 River Poddle
Dublin

The River Poddle runs beneath Dublin Castle through the city center and toward Wellington Quay where it flows into the River Liffey. There are passageways to the Poddle that can be accessed by opening manhole covers and dropping into the water.

This is exactly what two men decided to do in 2012. They were caught on CCTV wearing waterproof clothing and gloves outside Dublin Castle. The Garda (Irish police) sub-aqua unit searched for the two men. But they couldn’t be found even though their voices were audible when the manhole cover was lifted.

Gardai thought that the men might be urban explorers scouting the tunnels, but others wondered if they could be searching for treasure. The waterways pass close to the Assay Office that holds gold and silver, and the Poddle Tunnel also goes beneath the Central Bank on Dame Street. As of this writing, nobody has identified the two men caught on camera in 2012.^[9]

1 The Streets Under Limerick

In the early 20th century, Limerick’s aboveground streets were renamed after the Irish Free State was established. Beneath every renamed street, however, lies a sewer with its original English name. For example, when you walk down O’Connell Street, you are directly above George’s Street (which was named after King George III).^[10]

Supposedly, it was once possible to walk from one side of Limerick to the other completely underground. However, many of the underground tunnels have been concreted over and only some can be found today.

Many holes in the tunnel ceilings show where coal was delivered into bunkers under the aboveground streets. At the time, the tunnels were connected to sewers and drained away rainwater. They must have been quite unpleasant to walk in.

10 Bone-Chilling Facts About The Catacombs Of Paris

About The Author: Alexa still lives in Ireland and will do so until the money runs out.

Sea level is so overrated. Wonders abound beneath our feet—sometimes a few meters, sometimes a few miles. Some require nine-figure excavations and a team of international researchers, others a modest shovel and flashlight.

Pioneering scientific experiments, macabre reminders of history both recent and remote, and life forms that eluded mankind’s discovery for millennia are just part of the sublime subterranean scene. Here are ten fascinating things happening underground.

Related: 10 Communities Of People Who Live Underground

10 The Search for Dark Matter

In an abandoned gold mine nearly 1.6 kilometers (1 mile) below the Black Hills of South Dakota, 250 scientists from 37 institutions have constructed the Sanford Underground Research Facility (SURF). Its mission is to significantly advance the elusive search for dark matter.

The project is called LUX-ZEPLIN. LUX stands for Large Underground Xenon, while ZEPLIN stands for ZonEd Proportional scintillation in Liquid Noble gases. Well, duh.

The goal is to solve what might be the last piece in dark matter existence’s puzzle. In layman’s terms, we’re well aware of the universe’s matter-centric occupants—everything from rocks, water, and gasses to protons, electrons, and subatomic particles. The problem is that their combined mass doesn’t equal that of the universe—not by a long shot, actually.

To solve this riddle, LUX-ZEPLIN intends to record the presence of a physics unicorn of sorts: a weakly interacting massive particle with the apt acronym WIMP. The task involves a 1.5-meter-tall (five-foot) tank filled with about one-quarter of the world’s annual supply of liquid xenon. The hope is that, should a WIMP pass through, it might glance off a xenon nucleus, which would emit a flash of light or photon—allowing scientists to “see” dark matter.

The site’s exceptionally subterranean location is designed to block the humming interference in the world around us, long an obstacle to the search for dark matter. The experiment is set to run for about five years.^[1]

9 20,000 Corpses Under a Public Park

New York City is a modern metropolis whose early years often entailed a stunning lack of foresight. As late as the 1790s, officials failed to envision the already-bustling city growing more than a mile north, let alone consuming the 21.7-kilometer-long (13.5-mile) island of Manhattan.

In 1797, the city purchased farmland to create a potter’s field for the indigent, poor, criminals, and disease victims. The plot was less than a mile north of the city’s growing urban sprawl. Soon, Yellow Fever hit, with waves of the deadly, contagious disease ravaging New York City through 1803. The field began filling up, reaching capacity in the early 1820s.

In 1827, in a self-interest-driven real estate scheme, Mayor Philip Hone announced plans to transform the field into a public square. In the development rush, disinterment and reburial were completely foregone. The potter’s field was renamed “Washington Military Parade Ground”—a nod to the 50th anniversary of the country’s founding—before being shortened to Washington Square Park.

According to the 2005 book Inside the Apple: A Streetwise History of New York City: “While estimates vary, it seems likely that over 20,000 people were buried in the land… they remain to this day under the grass and pavement of Washington Square.”

The real estate scam paid off: The area’s property values soared 240% in the next five years, gobbled up largely by the college that would become New York University.^[2]

8 Extreme Resilience

Late last year, scores of species were found living in extreme cold and total darkness, 200 meters (650 feet) beneath the ice in one of the world’s most unforgiving habitats: Antarctica’s Ekström Ice Shelf. Seventy-seven distinct types of worms and moss animals called bryozoans were found in pitch-black waters of -2° (28°F). The cornucopia of creatures is changing how researchers consider the livability of such extreme submarine environments.

Though examples of some of these animals have been identified elsewhere in Antarctica, finding such a particularly foreboding locale teeming with life is a first. “This may give us clues into how life in polar seas survived glaciations,” said David Barnes, a marine ecologist with the British Antarctic Survey.

To access the surprising subterranean spot, researchers used a specialized hot water drill to bore through the ice, then dropped cameras down more than 60 stories. Carbon dating revealed that life had continuously existed there for nearly 6,000 years.

Other instances of unexpected existence have been found in Antarctica. In many, microbes seemingly subsist on pulverized bedrock in the sediment beneath the continent. On rare occasions, larger organisms also manage to survive, including sponges some half a mile below the ice—a discovery one researcher said was like “finding a bit of the rainforest in the middle of the Sahara.” While this latest discovery wasn’t as deep, it nonetheless expands the number of environments known to sustain life.^[3]

7 A City Under a City

With due respect to Edmonton and Ottawa, whose average winter temperatures are -7.3°C (18.8°F) and -6.5°C (20.3°F), respectively, Montreal is the coldest bonafide metropolis in North America. It is the second-coldest of its size in the world (Harbin, China is first, with a metro area of over 10 million and an average wintertime temperature of an insane -11.8°C or 10.8°F).

Montreal’s average is just -6.2°C (20.8°F) in winter and, due to its location right on the St. Lawrence River, feels far frostier. Through the decades, the city has perfected a novel way to combat the cold: burrowing beneath it. Just under the frigid feet of those at street level is an immense network of malls, tunnels, and transportation systems that allow Montrealers to literally stay under the weather.

Called le Réso, the network comprises over 32 kilometers (20 miles) of walkways connecting subway stations, office buildings, and housing complexes, much of it lined with top-notch shopping and dining. So commonplace and comprehensive is Montreal’s subterranean lifestyle that many commuters don’t even bother taking a coat with them to work because their day simply doesn’t include stepping outside at all. Ditto for students and visitors, who can leave dorms or hotels and reach schools, universities, museums, theaters, and more…all without packing a jacket.

Montreal’s underground is also an attraction unto itself, featuring such charms as a skating rink and regular public space art exhibitions.^[4]

6 Nothing, Unfortunately

No list of underground marvels would be complete without a legend that has birthed arguably the stupidest show in television history. I’m talking, of course, about The Curse of Oak Island.

Located off the south shore of Nova Scotia, Canada, Oak Island is not large—about a mile long and half a mile wide. And for over two centuries, people have been searching for an alleged treasure whose origins could trace to any number of figures, from pirates Captain Kidd and Edward “Blackbeard” Teach to secret societies like the Freemasons and Knights Templar.

In 2006, Michigan brothers Rick and Marty Lagina bought a 50% stake in the company that owns the island and became the latest in a long line of treasure hunters. Since then, their fruitless adventures have gone from empty-handed to empty-headed, further lowering the IQ of reality television—which is saying a lot. Find trinkets, declare it means “something else must be out there,” repeat.

And repeat. And repeat. In 2021, The Curse of Oak Island completed its treasure-teasing eighth season. That’s 138 separate hour-long episodes of guys digging empty holes in the ground and speculating about where the next hole should be dug. It’s like watching a squirrel try to find a buried acorn—although, in the squirrel’s defense, the acorn is actually real. I guess it’s time to catch up on the emptiness of Season 9!^[5]

5 Nothing, Fortunately

On an unassuming Berlin street, just down the road from the sprawling Holocaust Memorial, is a parking lot surrounded by typical, 1980s-style concrete East German apartment buildings. Until 2006, no indication whatsoever existed of the ground’s dark historical significance. These days, a simple plaque informs passersby of what lies just a few feet beneath them: the bunker where Adolf Hitler met his end.

Sarcastically known by locals as the “Führerbunker Parking Lot,” the paved-over place was once a garden of the Reich Chancellery. It is where the Nazi leader spent the final 3½ months of his life, descending into its depths on January 16, 1945, when the bombing of Berlin became too dangerous to stay above ground. He would go on to celebrate his last birthday there—his gift was the first bursts of Soviet shells on Germany’s capital. Nine days later, he would marry his long-time girlfriend there and, the next day, commit suicide in his chambers. Some honeymoon.

Hitler’s final days were a mix of mania, paranoia, and for his fellow bunker mates, pending doom. As he conducted reviews of Berlin’s waning defenses, held meaningless yet hours-long military strategy sessions, and generally denied reality, those around him tried to wriggle away, making their best excuses for why their presence was no longer necessary.

While much of the bunker was destroyed in Berlin’s rebuilding, some sections remain. They have been sealed off to prevent vandalism—or, even worse, tributes.^[6]

4 Drug Smuggling

While a 3,218-kilometer-long (2,000-mile) wall spanning the border of the United States and Mexico might put a dent in record-high illegal migration, it likely wouldn’t do much to combat drug smuggling. Mexican cartels have long had the resources and incentives to take their underground business…well, underground.

Often, their U.S. destination of choice is San Diego, whose suburbs extend to the Mexico border. On its outskirts, the city offers vast industrial areas yielding the anonymity of large warehouse buildings. The result is a hidden underground highway whose terminus can serve as both a receiving and processing spot. So prolific is the practice that San Diego actually has its own Tunnel Task Force manned with local and federal agents.

The largest of such tunnels was discovered in March 2020 at a warehouse in the San Diego suburb of Otay Mesa. Nearly 1.5 kilometers (1 mile) long and 9 meters (30 feet) deep, agents described the ambitious passageway as the most sophisticated they had ever seen, with an extensive rail and cart system to rapidly transport drugs, forced air ventilation, and high-voltage electrical cables and panels.

Dubbed “Baja Metro” by border agents, the tunnel also had an elevator at its entrance and a complex drainage system. The bust seized more than two tons of drugs, including 590 kilograms (1,300 pounds) of cocaine, at an estimated value of $30 million.^[7]

3 The Doorway to Hell

In Turkmenistan’s remote Karakum Desert lies a tourist attraction that lures thousands each year. It’s called the Darvaza Gas Crater, and it’s a sterling example of both nature’s power and mankind’s stupidity.

In 1971, when the central Asian republic was part of the USSR, a team of Soviet geologists traveled to the Karakum Desert seeking oil (the country is rich in petroleum and natural gas). Upon discovering what they believed was a substantial oil field, they commenced drilling.

But they hadn’t hit oil—they’d hit a cavernous pocket of natural gas that couldn’t support their equipment’s weight. The site collapsed, swallowing their drilling rigs and triggering a domino effect in the crumbly sedimentary rock. By the time the ground stabilized, there were several open craters, the largest of which measured 70 meters (230 feet) across and 20 meters (65 feet) deep. Good work, everyone.

It gets even dumber. Shortly following the event, wildlife in the surrounding desert began to die off. This was due to the craters’ high levels of methane, which in addition to being dangerously flammable, depletes the oxygen supply in its vicinity.

So the scientists decided to light the crater on fire, hoping that all the potentially lethal natural gas would burn away in a few weeks. Their calculations were slightly off. Nicknamed the Gates of Hell, the craters have been burning bright for half a century.^[8]

2 Trees Talking

Recent scientific studies confirm that trees are far more alert, sophisticated, and social than initially thought. Underground, through roots connected via fungi, bacterial matter, or other plants, trees not only communicate information about environmental factors like drought and disease but can even “lend” each other nutrients or water. This exemplifies a far more collective approach to “survival of the fittest” than most nature experts believed trees could exhibit.

There’s even a neat name for the phenomenon: the Wood Wide Web, which is believed to predate the source of its derivative nickname, the World Wide Web, by about 500 million years. In 2019, an international study covering 1.2 million forest plots and nearly 30,000 species produced the first global map of the underground networks comprising this secretive world.

While certainly competing for sunlight above ground, below the surface, trees are strikingly collaborative. Through the web, trees send chemical, hormonal, and slow-pulsing electrical signals to relay information ranging from pending drought and parasitic threats to nutrient disruptions and potential soil toxins. The result is an early warning system aligning with a group-centric “rising tide lifts all ships” concept.

Much of the Wood Wide Web’s success is mycorrhizal, meaning it relies on symbiotic relationships between plants and fungi. Research reveals this system’s importance in limiting climate change through carbon storage and, concerningly, its fragile susceptibility to rising global temperatures.^[9]

1 The Largest Living Thing on Earth

Many people would be able to name the world’s largest animal, the blue whale. And perhaps they’d even come up with the world’s largest tree: the Giant Sequoia, whose tallest specimen currently stretches some 84 meters (275 feet) into the sky, with a base diameter of an astounding 11 meters (36½ feet).

But to find the world’s largest living thing, we must venture underground. Discovered in 1998, a single fungal organism in Oregon’s Malheur National Forest covers an area of 9 square kilometers (3½ square miles)! That’s one humongous fungus among us.

Called Armillaria ostoyae, the reason so few know about this record-holding life form is its almost exclusively subterranean existence. Armillaria ostoyae is not a mushroom but rather a network of fungal threads and cords called hyphae. A parasitic fungus, it infiltrates tree bark and root systems, spreading out across the forest floor to find new hosts to colonize. While parts of it do pop up from time to time to reproduce, the massive non-mushroom remains mostly out of sight.

Notably, fake photos of Armillaria ostoyae have recently circulated online. One shows a mushroom the size of a house, towering over dazzling spectators. Another shows a mushroom stalk as thick as a tree trunk. The fraudulent fungal photos have led to many duped, disappointed visitors to the national park.^[10]

While underground isn’t anyone’s favorite place to live, cultures throughout history have experimented with the idea in one way or another. Even today, one can visit the remains of many fascinating underground cities and structures around the world – from the haunted vaults below Edinburgh to the vast network of catacombs beneath Odessa.

10. Matmata Underground Houses, Tunisia

Matmata is a Berber-speaking town in southern Tunisia known for its unique, underground houses carved out of the hillside. Also known as troglodyte houses, they were originally built to protect against the harsh hot and cold seasons of the region. However, many of them now lie unused and in need of repairs, with a few converted into hotels or other tourist sites. (Thanks in large part due to the fact they were used in Star Wars.) While we’re not sure exactly when they were built, they could go as far back as the 11th century, when the first Berber-speaking population moved and settled in the area. 

The houses themselves are ingeniously built, with a network of tunnels connecting different sections like the living room, kitchen, and bedrooms. Apart from protection against tough weather, the fortified nature of the structures would have also protected against raiders and hostile states, as the Berber people were often persecuted by the more powerful Arab states in the region. 

9. Vladivostok Fortress, Russia

Built in the 19th century as a Russian imperial base, Vladivostok is now a historical site located in the far-eastern Primorsky Krai region. It was one of the most impressive maritime fortresses of its time, constructed primarily for defense against Japan and other enemy attacks from the east. For a long time, the fortified city and its underground chambers housed the imperial Russian fleet, making it a potential target during a major war. 

Today, the network of underground tunnels and bunkers beneath the port city has been turned into a heritage site, including a museum of objects that once belonged to the imperial Pacific fleet. Apart from vaults, passageways, and warehouses, the fortress also has a variety of bomb shelters and water reservoirs in case of a siege. Despite its age and wear-and-tear, the fortress remains in a relatively good condition, with much of its original structure still intact.

8. Coober Pedy Mining Town, Australia

The mining town of Coober Pedy in south Australia was built in 1915, after a large quantity of opals was accidentally discovered in the area by a little boy. By 1920, it had turned into a small city, as early residents began living and working underground to escape the extreme heat, building houses, churches, hotels, and small businesses to sustain the settlement. As demand for opals grew globally, Coober Pedy soon became a thriving center for opal mining, with miners and mining companies from all over the world flocking to the area to make their fortunes. 

As of now, Coober Pedy is still a working opal mining town, with about 60% of its total 3,500 population living underground. Despite the especially-harsh conditions of the region and limited natural resources, the town has managed to survive and turn itself into a popular tourist destination over the years. 

7. Tunnels Of Moose Jaw, Canada

The tunnels of Moose Jaw in Saskatchewan, Canada were built during the early 1900s, back when anti-Chinese hysteria was gaining ground across Canada and the United States – a historical phenomenon we now know as the Yellow Peril. They were extensively used to transport Chinese immigrants from the USA to Canada, as most of the entrances were hidden in the underground basements of legal Chinese migrants living above. Evidence suggests that these tunnels served as hideouts for long periods of time and were often targetted by Canadian law enforcement agencies, pointing towards a dark-yet-forgotten phase in Canada’s history. 

By the 1920s, the tunnels were used to transport liquor and other prohibited items during Canada’s Prohibition era, along with a slew of other criminal activities. Now, they’re a popular tourist attraction throughout the year, and one can even visit and explore the structure with one of the many guided tours available in the city. 

6. Derinkuyu, Turkey

Derinkuyu used to be a sprawling underground city in the historical province of Cappadocia, Turkey. According to the Turkish Department of Culture, it was built around the eighth century BC by the Phrygians – an Indo-European culture thriving in the Anatolian region around that time. The structure is more than 85 meters – or about 280 feet – deep in some places, complete with living quarters, stables, storage rooms, and ventilation shafts. 

While the city would have been home to more than 20,000 people at its peak during the Byzantine era, it fell into disuse some time after the Ottomans took over in the 15th century. It was rediscovered during an archeological expedition in 1963, and eventually opened to tourists in 1965. According to some theories, Derinkuyu served as an important center of refuge for the Christians persecuted during the first Islamic raids in the region. 

5. Edinburgh’s Vaults, Scotland

Also sometimes called the South Bridge Vaults, Edinburgh Vaults are a series of underground chambers beneath the South Bridge in Edinburgh, Scotland. They emerged around the same time as the construction of the bridge in 1788, and were originally used as underground workshops and storage for the tradesmen working above. 

As the city’s population grew, the vaults came to be associated with the darker parts of life in Edinburgh, as they were soon populated by gamblers, bootleggers, murderers, and other criminals. If one rumor is to be believed, they were home to two of the most notorious serial killers in Scottish history – William Burke and William Hare. 

The vaults were effectively shut down by the late 19th century, only to be rediscovered by a Scottish rugby player in the 1980s. Now, they’re considered one of the most haunted places in Scotland, thanks to a bunch of ghost sightings and other spooky phenomena observed in many of its 120 underground rooms over the years. 

4. Wieliczka Salt Mine, Poland

Wieliczka is one of the two salt mines located in the town of Wieliczka in southern Poland. It was built in the 13th century, when salt emerged as an expensive, sought-after commodity around the world, and has been in continuous operation ever since. The mine has since been expanded and further excavated by many generations of miners, with a whole network of underground chambers, halls, and passages spread over nine levels.

Apart from being a functional salt mine and one of the earliest centers of industrial activity in Europe, it’s also a cultural and historical site called the Wieliczka Salt Mine City. By the 19th century, the entire structure was turned into a giant art exhibition, with salt-carved monuments, crystal chandeliers, decorated chapels, and other artifacts spread across its 2,400 chambers. 

3. Berlin’s Atomic Bunkers, Germany

Berlin has been home to an extensive network of underground bunkers since at least the 1950s, when fortified underground structures came up as popular – even if untested – defense against nuclear weapons. While most of them were built as shelters for the Cold War, Berlin’s underground bunkers were surprisingly diverse, ranging from basic shelters to elaborate living spaces equipped with gas masks and other emergency survival equipment. 

As the Cold War came to an end with the fall of the Berlin wall in 1989, most of these bunkers were abandoned or turned into museums and art exhibition centers over the years. One can still run into the city’s underground music scene in one of these spaces, as many of them have been reopened and repurposed as live music venues in recent years. 

2. Odessa’s Catacombs, Ukraine

The city of Odessa in Ukraine boasts of the largest network of catacombs in the world, running across a total length of about 1,500 miles – or 2,500 kilometers. Originally carved out as a result of extensive limestone mining in the city in the 1600s, it’s now an entire underground city on its own, with over 1,000 known entrances and multiple chambers and passageways one can explore. Of course, one has to be particularly courageous to do that, as these catacombs have been used for some pretty dark reasons over the years. 

During the Second World War, the maze was used as a hideout by occupying Nazi forces, and one can still probably find bones and other relics of the war if they explore the more remote parts of the structure. They’ve also been used as shelters during air raids, and as hidden smuggling routes during Soviet times. 

1. Underground Great Wall, China

In the 1960s and ’70s, Chairman Mao ordered the construction of thousands of underground shelters and settlements across China, thanks to the growing threat of nuclear warfare around the world. In Beijing alone, more than 10,000 shelters were constructed to protect the capital’s growing urban population. 

Due to its vastness and military-related objectives, the entire structure – which once covered an area of more than 85 square kilometers, or about 33 square miles – is also sometimes called the Underground Great Wall. According to accounts, the network included schools, movie theaters, barber shops, restaurants, shops, factories, ammunition arsenals, fortified bunkers, and pretty much everything else required to live underground for extended periods of time. Some parts were privatized and sold to smaller landlords, which were then converted into tiny residential units over time. Today, more than a million people live or work in the underground city.