From the comfort of your own home, you can tackle these 10 unsolved coded puzzles that have baffled even the sharpest minds. Some of these riddles hide the route to buried treasure, others guard the secrets of unsolved murders, and a few simply promise the bragging rights of being the first to decipher a mystery that has lasted for decades.
10 Unsolved Coded Secrets Await
10 Forest Fenn’s Buried Treasure
When affluent art collector Forrest Fenn was diagnosed with cancer, he decided to leave behind a legacy that would remind future generations of his adventurous spirit. He concealed more than a million dollars’ worth of gold nuggets, historic coins, and priceless jewelry somewhere in the rugged mountains north of Santa Fe. In 2011, Fenn published a memoir that contained nine cryptic riddles intended to guide treasure hunters to the exact spot.
The chest is reputed to be brimming with glittering coins, hefty gold nuggets, ornate statues, and dazzling jewelry—items that have appreciated in value since they were first hidden. The hunt has been so fierce that enthusiasts have literally risked their lives. In 2016, a man named Randy Bilyeu tragically died while searching for the gold.
Following Bilyeu’s death, Fenn publicly stressed, “The treasure is not hidden in a dangerous place. I’ve said many times not to look for the treasure any place where an 80‑year‑old man couldn’t put it.”
9 The Somerton Man Cipher
In 1948, a man’s body was discovered on an Australian beach, forever known as the Somerton Man. No identification was found, but tucked in his pocket was a slip of paper bearing the Persian phrase “Tamam Shud” (meaning “It is finished”).
Decades later, investigators revealed that the victim had torn the paper from a copy of the Rubaiyat of Omar Khayyam. In the back of that book, he left a baffling series of letters:
WRGOABABD
MLIAOI
WTBIMPANETP
MLIABOAIAQC
ITTMTSAMSTGAB
Former UK detective Gordon Cramer believes that microscopic writing is hidden between the letters, amounting to roughly 1,100 characters, and that the concealed code might expose British military secrets. His theory remains controversial, and the cipher stays unsolved.
8 The D‑Day Pigeon
When Allied forces stormed the Normandy beaches on D‑Day, the British army operated under a total radio blackout. To convey vital intelligence back to England, officers attached encoded messages to the legs of carrier pigeons.
One pigeon lost her way, becoming wedged in a chimney for seven decades until a homeowner uncovered her skeletal remains during renovations. Inside a tiny red capsule attached to the bird’s leg was a cryptic string of letters:
AOAKN HVPKD FNFJW YIDDC
RQXSR DJHFP GOVFN MIAPX
PABUZ WYYNP CMPNW HJRZH
NLXKG MEMKK ONOIB AKEEQ
WAOTA RBQRH DJOFM TPZEH
LKXGH RGGHT JRZCQ FNKTQ
KLDTS FQIRW AOAKN 27 1525/6
In 2012, code‑breaking experts admitted defeat, stating that without the original code books, any additional encryption details, or contextual clues, the message would remain indecipherable.
7 Tatjana J. Van Vark’s Haiku
Tatjana J. van Vark straddles the line between engineer and artist, crafting intricate machines that often echo the technology of bygone eras. Though many of her creations are more aesthetic than functional, they showcase astonishing technical prowess.
Van Vark is celebrated for engineering feats such as building an oscilloscope from scratch at just 14 years old. She has also designed a cryptographic device she claims improves upon the historic Enigma machine. In exchange for revealing the inner workings of her invention, she challenges solvers to decode a cryptic haiku she programmed into the device:
GUK59 XBOFJ
-AFF1 SGU65 0‑KME YKCL7
76PRO LIKNY /WVSZ X‑JYI OS6GN 9GLYL
CTOSE -UBO6 OFD7P I+M3J
IOP59 O0/6T 10G2Q
Despite its brevity, the poem resists all attempts at decryption, leaving the mechanism of Van Vark’s machine shrouded in mystery.
6 The Devil’s Handwriting
First printed in 1539, this enigmatic inscription has never been deciphered. Legend attributes the text to Ludovico Spoletano, who allegedly summoned the Devil to take over his hand and inscribe a bizarre, scratched message.
The tale taps into the 16th‑century fascination with the supernatural. Spoletano’s alphabet bears a striking resemblance to Amharic, which was once believed to be the tongue spoken in the Garden of Eden.
Scholars generally dismiss the demonic origin story, treating the piece as a conventional cipher awaiting a breakthrough. Until someone cracks Spoletano’s code, the true meaning remains locked away.
5 Papyrus Oxyrhynchus 90
An Egyptian papyrus dated to AD 180 serves as a mundane receipt for corn purchased from a public granary. Yet, tucked at the bottom of the document are two lines of Greek characters that defy interpretation.
The two inscrutable lines appear to form a coded message, as illustrated in the accompanying image. First made public in 1898, the papyrus attracted the attention of Frederic Kenyon, a handwriting expert at the British Museum, who attempted a decipher in 1907. Neither Kenyon nor any subsequent scholar has succeeded.
To this day, the cryptic Greek script remains an unsolved puzzle, tantalizing historians and code enthusiasts alike.
4 The Cipher Of The Zodiac Killer
During 1968‑1969, the Zodiac Killer terrorized the San Francisco area, demanding that local newspapers publish a series of cryptic messages. The public was set alight with speculation as amateur sleuths raced to decode the killer’s ciphers.
The initial message was solved within days, but later ciphers grew increasingly complex. One particular 340‑character cipher still eludes decryption, drawing worldwide attention from code‑breakers.
In 2012, amateur analyst Corey Starliper claimed a breakthrough by substituting symbols with look‑alike letters and then shifting each letter three places forward in the alphabet. His translation produced a chilling note ending with, “Please help me stop killing people. Please. My name is Leigh Allen.”
Professional cryptographers dismissed Starliper’s solution as fabricated, arguing that he arbitrarily altered rules to produce his desired outcome.
3 The YOG’TZE Case
Before his 1984 death, Gunther Stoll warned his wife that an unknown “they” were stalking him, threatening his life. On the day he died, he shouted, “I’ve got it!” and scribbled the cryptic word “YOG’TZE” on a scrap of paper before fleeing his home.
Later that night, Stoll’s body was discovered in a crashed car, naked, with only the paper bearing “YOG’TZE” beside him. Initial police reports suggested a drunken accident, but an autopsy revealed he had not been driving; he had been run over and placed in the vehicle by his murderer.
The meaning of “YOG’TZE” remains a mystery, and many suspect the phrase may hold the key to identifying the unseen stalker who orchestrated Stoll’s demise.
2 Kryptos
In 1990, sculptor Jim Sanborn installed a massive metal artwork titled Kryptos at the CIA headquarters. The piece bears 865 characters split across four distinct ciphers, deliberately crafted as a challenge for the nation’s brightest minds.
The first three sections were cracked early on: an NSA employee solved one in 1993, a CIA analyst followed in 1998, and in 1999, Jim Gillogly became the first private citizen to decode them. The fourth segment, however, remains stubbornly unsolved.
The elusive fourth part reads:
OBKR
UOXOGHULBSOLIFBBWFLRVQQPRNGKSSO
TWTQSJQSSEKZZWATJKLUDIAWINFBNYP
VTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
In 2010, Sanborn disclosed that the sequence “NYPVTT” translates to “Berlin,” and four years later revealed that “MZFPK” corresponds to “clock.” He hinted that several intriguing clocks exist in Berlin, urging solvers to investigate further.
1 The Blitz Cipher
During World War II, a series of bombs detonated over an East London cellar, exposing a collection of papers inscribed with an exotic, beautifully rendered alphabet. The script, unlike any known language, defies all attempts at translation.
The first sheet bears a plaque with cryptic lettering beneath it. Subsequent pages contain intricate diagrams and a grid densely populated with cipher symbols.
To date, eight pages have been released, yet scholars cannot determine the meaning or the author of the script. Some theorists propose the documents belong to a secret society over a century old; others argue they are an elaborate hoax designed to amuse future generations.
Whichever the truth, the individual who finally deciphers the Blitz Cipher will be celebrated as the pioneer who unlocked a long‑lost enigma.