Sewers and drains are more vital to civilization than many people in the modern world realize. Before the advent of widespread sanitation, waste and grime were often hurled out of windows onto streets—or even onto the heads of unsuspecting passersby.

Today we simply press a lever and never really think about where our unwanted leftovers travel. Yet these underground arteries collect far more than just sewage, often swallowing the odd and unexpected. Below are the 10 strangest things ever uncovered beneath our feet.

10 Strangest Things Found in Sewers

10 A Rave

Imagine a midnight rave hidden in a concrete tunnel—who could resist the allure of dancing under the city’s veins?

Now picture that party taking place inside a sewer!

Back in 2017, more than two hundred thrill‑seekers in Newcastle, England, waded through grimy water to discover a dry alcove within the storm‑drain that feeds the River Ouseburn. The gathering was coordinated on Facebook, with participants meeting at a local pub before plunging into the underground channel.

Inside, they found a full‑blown light and sound rig already set up, and the festivities kicked off. At around 4 a.m., one reveler began to feel the cramped, damp environment getting too oppressive. Concerned for everyone’s safety, they dialed the police.

Authorities arrived, shut down the impromptu concert, and escorted the crowd out, issuing a stern reminder about the hazards of mixing alcohol with confined, flood‑prone tunnels.

9 Fatberg

When we flush away the unsavory bits of daily life, we hope they’ll never resurface to haunt us. For the brave souls who maintain our underground networks, however, our careless disposals can combine into true monsters.

The 2017 London fatberg stretched over 250 metres (820 ft) and resembled a rotting, congealed serpent. Inside the city’s sewers, stubborn items such as diapers, wet wipes and condoms tangled with solidifying fats, creating a blockage that threatened to spill raw sewage onto the streets above.

Weighing as much as nineteen African elephants, the beast was finally broken apart by workers wielding spades and high‑pressure water jets. Yet the fatberg proved more than a nuisance; it became a piece of urban history.

The Museum of London managed to acquire a chunk for posterity. Curators had to X‑ray the greasy mass for hidden hypodermic needles and don bio‑hazard gear. After stabilising the sample to halt decay and fly‑hatching, it now stars in the museum’s dedicated fatberg display.

8 An Alligator

One of New York’s most persistent urban legends claims that the city’s sewers are teeming with alligators. Supposedly, people bought baby gators as novelty pets, soon discovered they’re terrible companions, and flushed them down the toilet.

Folks say the reptiles now prowl the underground waterways. In reality, there’s no solid evidence of a thriving alligator colony beneath Manhattan, and experts agree the climate is far too cold for long‑term survival. Nonetheless, a 2.4‑metre (8‑ft) alligator was recovered from an East Harlem manhole in 1935, leaving the mystery of its arrival unsolved.

In regions where alligators naturally belong, sightings in drains are less odd. If you peer into a dark pipe and glimpse gleaming eyes, it might be a gator, not a mythic monster.

In Florida, rain‑driven floods have forced alligators into storm drains, where they are later hooked out. In Louisiana, a 3‑metre (10‑ft) alligator was spotted waddling out of a drain before taking a nap on a suburban porch.

7 A Cow

Not every subterranean visitor is a fearsome predator. When a bovine was discovered in a British sewer, it was already deceased and rather placid, yet live cows have been found underground as well.

In China’s Fujian Province, a farmer searched for a missing cow for four days. Just as hope waned, a strange moo echoed from beneath the village. Lifting a manhole cover revealed the bewildered animal poking its head out. Villagers rigged a makeshift winch and hauled the cow to the surface, where it emerged unharmed, though its underground escapade remained a mystery.

Across the world in India, a calf slipped into an open sewer and was carried away by the flow. A brave passerby dove into the foul water to rescue the youngster. Both animal and rescuer survived, albeit with a lingering scent of sewage.

6 A Sewer Monster

In 2009, a video purported to show an alien‑like monster pulsating on a North Carolina sewer wall went viral. The eerie pink mass seemed to pulse and writhe, sparking wild speculation about extraterrestrials targeting our drainage systems.

Scientists quickly identified the source: a dense colony of Tubifex worms, common segmented worms that thrive in moist soils. The apparent throbbing was likely caused by the camera’s hot light, which can make the worms’ bodies contract rhythmically.

While the worms themselves are ordinary, their sudden appearance in a sewer was unexpected, baffling even seasoned workers who had never seen such a gathering of these slimy creatures.

5 A Baby

In China, a frantic woman heard a baby’s cries emanating from a drain beneath a toilet. She called emergency services, and rescuers spent two harrowing hours extracting the infant—still alive—from the pipe where it had become wedged.

Police soon realised the woman who raised the alarm was also the mother. Overcome with labor while using the toilet, she delivered the child herself, only to watch the newborn slip down the sewer line.

The tragedy stemmed from an absent father who refused to support the baby, leaving the mother to face the ordeal alone. A similar incident occurred in South Africa, where a newborn, aged between one and three days, was found screaming in a storm drain. After four grueling hours of drilling and chiselling, rescuers pulled the child out, and she was later named Sibanisethu—“Our Ray of Light”—by the local community.

4 A Community

Las Vegas is a city of extremes, famed for its neon lights and relentless gambling. When the desert climate is bone‑dry, the city is parched; when rain arrives, torrents can flood the streets.

To combat flooding, the municipality built roughly 1,600 kilometres (1,000 mi) of storm‑drain tunnels to channel rainwater away. Over time, these conduits began to serve another purpose: shelter for the city’s homeless population, giving rise to the “tunnel people” of Las Vegas.

The cramped, dimly lit passages are home to scorpions, graffiti, and those down on their luck. When heavy rain strikes, the tunnel dwellers risk losing everything—including their lives—to sudden floodwaters. Estimates suggest hundreds of people may be living beneath the Strip, though the exact number remains unknown.

Some tunnel residents hold low‑wage jobs and retreat to the sewers only to sleep, while others spend most of their days in the shadowy corridors, forming a hidden community beneath the city’s glittering façade.

3 Gold

Beyond the occasional accidental loss of valuables, sewers might actually be a hidden treasure trove. Scientists estimate that nearly $2 million worth of gold—and a similar amount of silver—flows through Switzerland’s sewage system each year.

Much of this precious metal likely originates from tiny flakes shed by the country’s renowned jewelry and watchmaking industries. In locales dense with goldsmiths, sifting through sludge could yield more glimmer than a traditional mine.

In Japan’s Suwa, researchers have already extracted gold from sewage sludge. By incinerating the waste, they produced ash containing roughly 2 kilograms (4.4 lb) of gold per ton—an ore grade richer than many conventional gold mines.

2 Drugs

Everything that passes through a human body eventually finds its way into the sewer network, and that includes pharmaceuticals and illicit substances. These chemicals can cause serious environmental issues. For instance, contraceptive hormones from birth‑control pills enter waterways, disrupting fish reproduction and leading to population declines.

Researchers also analyse sewage to gauge community drug use. By testing wastewater at treatment plants, scientists have uncovered patterns showing spikes in marijuana, cocaine, and methamphetamine consumption during festivals and holidays.

Occasionally, the sewers hide more than just waste. In Palermo, police uncovered 77 thriving marijuana plants growing clandestinely beneath the city’s underground tunnels.

1 Snakes

Few moments are as vulnerable as when we’re perched on the toilet. In that brief pause, the phone may ring, the doorbell may buzz, or—if you’re unlucky—a snake might decide to bite you right where you’re sitting.

Snakes turning up in toilets is a genuine phenomenon. In Australia, a woman startled a carpet python that had slipped into her bathroom, earning her several puncture marks on her backside.

These reptiles often infiltrate homes by following rats that use sewers as escape routes. Once inside the bowl, a snake may linger, treating the porcelain throne as a temporary hideout until an unsuspecting occupant arrives.

The menace isn’t confined to the Land Down Under. Reports of snakes emerging from toilets have surfaced across the globe—from Texas to Seattle, South Africa to the UK’s Southend. So next time nature calls, you might want to glance under the seat before you sit.

If you had to make a list of places you never want to go, a sewer has to rank on there somewhere. You don’t need to experience one to know you won’t enjoy it. Depending on the sewer and its location you can expect to find human waste, cockroaches, rats, trash and a whole host of other unpleasantries. And that’s just the usual contents of a sewer. Sometimes it gets even weirder. 10 nightmares discovered beneath our cities prove just how bizarre the underground can become.

10 A Lion Once Got Loose in the Sewers of Birmingham, England

Nothing should live in a sewer but that doesn’t mean nothing does. As mentioned, rats and roaches can make a fine home in the damp, dark tunnels beneath our feet and there’s not a lot to be done about it. But in 1889 a much larger resident set up shop in the sewers beneath Birmingham, England.

A traveling menagerie—a sort of roaming zoo—was in town and they had their exotic animal collection on display. Among them was a male lion that managed to break free and sprinted straight into the local sewer system. This particular lion had already mauled one person and killed another, so it was far from a cute circus mishap.

To calm the growing panic, the menagerie owner pulled a clever trick: he slipped a second lion out of the show and pretended to capture it at a different sewer entrance. Since no one had seen a second lion escape, the owner was hailed as a hero for “catching” the beast. In reality, he later confessed the ruse to the police, who then helped him actually capture the escaped lion a day later.

9 A Nile Crocodile Was Discovered in Paris Sewers

In 1984, workers in Paris uncovered one of the most unlikely creatures to be found in a sewer—a Nile crocodile. The baby croc, named Eleanor, had been feasting on rats near an entrance to the Seine River.

Even though a rat‑eating crocodile might sound like a handy pest controller, the city still captured the animal and temporarily placed it in a zoo. Afterward it was moved to an aquarium in Vannes, where it spent most of its remaining years.

The Vannes aquarium closed in 2020 when Eleanor was 38. She was transferred to a sanctuary called La Ferme aux Crocodiles, but unfortunately she didn’t survive the relocation and died shortly thereafter. It is believed Eleanor had been illegally imported and abandoned once she outgrew the size and danger she posed.

8 British Sewer Workers Had to Deal With a 130 Ton Sewer Fatberg

Misplaced animals in a sewer are one thing, but a fatberg is an entirely different nightmare. That’s the nickname we give to monstrous clumps of goop that choke modern sewers when people flush too much junk for the system to handle.

Things like baby wipes, which don’t disintegrate like toilet paper, combine with grease, human waste, and other trash to create massive, solidified masses that can halt flow entirely. One of the biggest on record was discovered in Whitechapel, East London—a 130‑ton monster that required a team of trained professionals to dismantle.

While the sheer grossness of the blob—laden with cooking oil, used condoms, and old tampons—might elicit giggles, the health risks are serious. The congealed fat and waste hide bacteria, disease, and even hazardous objects like needles, putting workers in danger. The public became oddly fascinated, and pieces of the fatberg were preserved by the Museum of London, despite the challenges of mold and flies that kept appearing on the salvaged chunks.

7 Thousands of Bucharest Orphans Live Below the City

There’s another kind of nightmare you can find in sewers that isn’t about creepy critters. In Bucharest, thousands of orphans have taken up residence in the city’s underground tunnels. The former communist regime had banned both abortion and contraception, resulting in an estimated 100,000+ orphaned children.

When the Romanian Communist regime collapsed in 1989, every state‑run orphanage was abruptly shut down. The children were literally cast onto the streets to fend for themselves. The sewers of Bucharest, equipped with steam pipes that provided warmth, became a refuge for many, and they have remained there ever since, even forming families beneath the streets.

Life in those tunnels is far from idyllic. Residents have struggled with addiction, illness—including HIV and tuberculosis—and the constant threat of the harsh underground environment.

6 Sydney Has Had Giant Snapping Turtles in the Sewer

We’ve seen how sewers across Europe are beset by unexpected visitors, but the phenomenon isn’t limited to the continent. Sydney, Australia, has its own subterranean drama in the form of snapping turtles.

An alligator snapping turtle named Leonardo is Australia’s most famous sewer resident. After being rescued, he was sent to a zoo where he grew to over 100 lb. Fans rallied in 2016, gathering more than 16,000 signatures to persuade the zoo to provide a larger enclosure, as Leonardo had doubled in size since his capture.

It’s believed the turtle was smuggled into Australia and then illegally dumped in a drain. When first discovered in the sewer in 2000, he weighed just 55 lb and was briefly nicknamed “Cowabunga.” Alligator snapping turtles can exceed 200 lb, and their powerful jaws can bite off a human finger. Though native to North America, there’s speculation that Leonardo may have been stolen from a zoo display in 1979.

5 North Carolina Had a Viral Sewer Monster

When you want to see a true sewer monster, you need to head to the internet. That’s where most people first saw something no one could explain back in 2009. This sewer monster was discovered in Raleigh, North Carolina, and for a while people thought it had to be a hoax or even a promo for some kind of found‑footage movie.

A viral video showed a writhing, pulsating thing that would have fit right into a Hellraiser film. After some sleuthing, it turned out the “monster” was actually a colony of tubifex worms. These worms inhabit sewers, attaching themselves to roots that have broken through bricks and cracks in the walls.

The camera lights disturbed the worms, causing them to pulse and retract, creating the illusion of a single, mysterious creature. Some also suggested the footage could be a colony of bryozoans—tiny, creepy organisms most of us never see in daylight.

4 An Ancient Roman Wrote About an Octopus Breaking in Through the Sewer

The ancient Romans learned the art of making sewers from the Etruscans and deployed them throughout the empire. Just like modern sewers, these ancient conduits attracted unwanted guests. Because some Roman sewers connected directly to the open sea, they opened the door to more exotic visitors.

Writer Aelian recorded a tale that has survived through the ages: an Iberian merchant was plagued by nightly visits from an octopus that slithered up from the sea, crawled through the sewer, and invaded his home.

Octopuses are renowned for their intelligence and ability to squeeze through tight spaces. This particular octopus would raid the merchant’s pantry, stealing his pickled fish and causing quite the nocturnal nuisance.

3 Snake Nests Are Not Uncommon in Sewers

The internet is full of “snake in a toilet” videos, featuring reptiles from Australia, South America, Africa, Asia, and North America. Arizona, for example, is no stranger to toilet snakes.

Many snakes find their way into a toilet from the outside, seeking a cool, damp refuge during heat waves. Some, however, take the longer route, navigating through sewers. For every snake that ends up in a toilet, countless more likely remain hidden in the drainage system.

In Thailand, a flood in 2022 disturbed a sewer, exposing a colony of over 100 baby snakes. Local residents rescued the serpents, gently fishing them out and placing them on dry land. A similar incident occurred in Washington state in 2014, when a contractor discovered half a dozen snakes trapped in a clogged line—presumed to be pets someone had flushed.

2 Piranha Fish Have Made Their Way to UK Sewers

Just because something fits in a toilet doesn’t mean it’s a good idea to flush it. In the town of Chichester, England, a piranha was discovered in the local sewers in 2018, prompting the water company to remind residents to only flush waste.

These freshwater fish are famed for their sharp teeth and carnivorous reputation, though in reality they rarely harm humans. However, they are an invasive species, not native to Europe, and if a breeding population were established, it would threaten local ecosystems and pose risks for sewer workers.

1 Dozens of Corpses From a Cemetery Were Found During a New Sewer Excavation

Short of evil clowns, few things are as unsettling as finding actual human bodies in a sewer. In 2023, workers in Evansville, Indiana, uncovered almost 70 corpses while constructing a new sewer beneath a former church site.

No one had known that an old cemetery lay beneath the area, dating back over 200 years—older than the town itself. As the crew dug, they unintentionally disinterred the remains. The bodies were discovered gradually, and plans were made to properly rebury each set of remains as they emerged.

Officials were aware a cemetery existed in the vicinity, but because it had never been officially marked, its exact location remained unknown. The discovery shocked the city, revealing a hidden burial ground that had lain undisturbed for centuries.