There’s a lot we know for certain about the US – it has vibrant cities, diverse national parks and some of the world’s best burgers. But from baffling disappearances, famous cold cases and cryptic messages, to unexplained phenomena and peculiar legends, there is still so much left to our imaginations. Here, we scour the annals of history for the greatest unsolved mysteries that continue to haunt America, challenging all reason and sparking endless conspiracy theories. Will the truth ever be revealed?

Click through the gallery to discover 25 enduring American enigmas we may never find the answers to...

The first English settlement in the New World, located off the coast of present-day North Carolina, was found mysteriously abandoned in 1590. When the mayor of the colony returned after a three-year absence with supplies for his 115 denizens, not a soul was left on Roanoke Island. Only two clues remained as to what might have unfolded – the words ‘Croatoan’ and ‘Cro’ carved into wood nearby. Could the community have been attacked by, or assimilated into, the Native American Croatoan tribe who lived on the neighbouring island? Perhaps they just relocated, or were lost at sea attempting to reach England? To this day, the truth remains unknown.

He’s tall, he’s hairy and he's believed by some to stalk the forests of the Pacific Northwest. Since the 1950s, reports of a large, bipedal ape-like creature have been especially prevalent in these parts, with alleged sightings, footprints and photographs of the perceived primate-slash-wildman only feeding the centuries-old legend. The FBI have even had an investigative file on the iconic cryptid, also known as Sasquatch, since 1976. But who – and what – is Bigfoot, really? While some scientists have theorised that he could be a remnant of the Neanderthal race, it’s more likely to simply be a case of mistaken identity or an elaborate hoax.

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On 2 July 1937, trailblazing American aviator Amelia Earhart and her navigator departed New Guinea on the final stages of their quest to circumnavigate the globe. But over the Pacific Ocean, their plane (known to be low on fuel) lost contact with the US Coast Guard. What happened next is an enigma; the pair never arrived at their next destination, but no evidence of a crash, nor their bodies, has ever been recovered. Earhart was declared legally dead in January 1939, but that didn’t stop the competing conspiracies around her disappearance. Whether she became a castaway, was taken prisoner by the Japanese, or something else, the mystery endures.

It was a campaign of terror of which the ripples were felt for decades, resulting in five known murders (though the culprit claimed to have committed at least 37). The so-called Zodiac Killer, whose crimes and cryptic public letters shook northern California in the late 1960s, has never been officially unmasked, but his haunting legacy lingers. Alongside his capital crimes, the Zodiac published coded messages in newspapers and goaded the cops, before abruptly stopping. Though a team of cold case investigators believed they’d uncovered the serial killer’s identity in 2021, the FBI and San Francisco Police Department dismissed the findings, leaving the case open.

Formed just before the American Civil War, the Knights of the Golden Circle (KGC for short) was a clandestine society of Southern aristocrats, united by pro-slavery politics and the desire to create a Confederate empire. While it had a few high-profile members, little is known about the finer details of the group or why it disappeared into obscurity after the war. The man who shot Abraham Lincoln, John Wilkes Booth (pictured), was supposedly a member, leading some to speculate that the president’s assassination was a KGC plot. Other popular theories suggest that the group may still secretly exist today, and that its wealth is hidden somewhere in the US.

Surrounded by the bleak waters of San Francisco Bay, Alcatraz served as a maximum-security prison between 1934 and 1963. It was regarded as inescapable – until three inmates seemingly achieved the impossible in 1962. After digging their way through the prison walls with sharpened spoons and leaving papier-maché dummies in their beds, Frank Morris, John Anglin and Clarence Anglin rowed their makeshift raft into the proverbial sunset, if the tale is to be believed. But did the trio really make it safely to shore? There have been no confirmed sightings of them in the years since, but no bodies matching their descriptions were ever found either.

On the edge of the Chihuahuan Desert, the remote Texan town of Marfa is the setting of a strange phenomenon that has lasted more than 140 years. The ‘ghost lights’ of Marfa were first reported in 1883 and are described as dancing, pulsating orbs of coloured light in the sky. But even now, no one can explain for sure what they are, or what causes them. Conspiracy theories have ranged from UFOs and falling stars, to the souls of deceased conquistadors haunting the plains, to car headlights and campfires. Their appearances are unpredictable, only occurring around a dozen nights of the year, which adds to the mystique.

Supposedly hidden somewhere in rural southwestern Virginia is a 200-year-old treasure hoard. Worth an estimated $54 million (£42m) today, it’s thought to have been buried by frontiersman Thomas J. Beale, who purportedly happened across the fortune on a hunting trip. Beale then concealed the details of the treasure behind a set of three puzzles. So far, only one of the ciphers has been decrypted. The rest have eluded cryptanalysts, conspiracy theorists, computer scientists and even the military over the years, leaving us no closer to knowing the vault’s location – if there’s even a vault at all. Inconsistencies in Beale’s discovery story have cast doubt on its legitimacy.

From their creation to their obliteration, the Georgia Guidestones never ceased to baffle. Dubbed ‘America’s Stonehenge’, the granite monoliths were erected outside the city of Elberton in 1980. Inscribed with 10 controversial guidelines for a post-apocalyptic society, they were commissioned by a mystery man using a pseudonym, working on behalf of an anonymous collective. Critics labelled the stones satanic and called for their destruction, getting their wish in 2022 when the monument was irreparably damaged in a deliberate explosion. But who lit the fuse – and who was behind the false name? There are still no certain answers to either question, only wild conjectures.  

On 24 November 1971, infamous hijacker D.B. Cooper boarded a plane from Portland to Seattle and claimed he had a bomb. After demanding a large ransom and parachutes, Cooper allowed the aircraft to deplane in Seattle, where it refuelled and headed for Mexico, via Reno, as per Cooper’s instructions. But by the time the plane got to Reno, Cooper was nowhere to be found. Several packets of his ransom money were identified in Oregon in 1980 (pictured), but no sign of Cooper himself. He’d vanished almost without trace, save for a black tie left on his seat, and a parachute strap recovered in 2017 from Cooper’s possible landing site.

Area 51 has served as a US Air Force base since 1955, but didn’t become public knowledge until 2013, when the CIA finally came clean about its existence. It was here that Cold War spy planes were tested and developed – and where the remains of crashed alien spaceships are housed, if you buy into the gossip. Further whispers implicate Area 51 in a conspiracy to fake the Apollo moon landing. Regardless of what really goes on here, the experiences of former employees have done little to debunk the site’s bizarre reputation; no official documentation connects them to ever having worked at Area 51, and salaries were paid in cash.

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History remembers it as one of the most mystifying terrorist attacks to ever strike America: a horse-drawn cart, rigged with dynamite, exploding in the middle of Manhattan’s Financial District. It occurred on 16 September 1920, when the streets bustled with stockbrokers, stenographers and bank clerks during the lunchtime rush. The blast killed 38 people and left hundreds wounded. But who was responsible for what was to be the deadliest act of terror on US soil for 75 years? Despite communist and anarchist groups being prime suspects, no one has ever been charged, leaving the exact motive and target up for debate too.

Cold War-era paranoia led to an inherent distrust of the unknown. When debris from a 'flying disk' was found just outside Roswell, New Mexico, in 1947, America descended into a frenzy. Though officials attempted to write the item off as the remains of a weather balloon, many believed it to be of extraterrestrial origin – the ‘crash site’ is now one of several UFO-themed tourist attractions in Roswell. Nearly 50 years after the discovery, the US military finally admitted that the craft was connected to a top-secret atomic espionage mission. But even if the alien spaceship theory doesn’t check out, the truth remains cloaked in conspiracy.

Almost 80 years have elapsed since 22-year-old aspiring actress Elizabeth Short (pictured), labelled the ‘Black Dahlia’ by the media, was found brutally murdered and mutilated in the LA neighbourhood of Leimert Park. It's one of the oldest cold cases in the city, having confounded the police, the press and amateur sleuths alike. The gruesome crime was investigated by hundreds of officers, who interviewed anyone they could track down with even the most tenuous connection to Short around the time of the death. Not a single suspect was arrested though, and all leads fizzled into failure and false confessions.

The site of the largest pre-Columbian settlement north of Mexico, the Cahokia Mounds are all that’s left of North America’s first major city. At its peak, Cahokia rivalled London for size and was home to some 20,000 Indigenous peoples, before becoming mysteriously deserted by AD 1350. War, disease, environmental disasters and European colonisation have all been dismissed as potential causes for the abandonment, and references to Cahokia haven’t even survived in Native American teachings and oral storytelling traditions. So, what could possibly have happened here that led to the city being erased from living memory? We can never be sure.

This curious phenomenon, often described as an orange, fiery ball of light, has been occasionally spotted flickering above the borderlands between Missouri and Oklahoma. According to urban myth, the mysterious orb first appeared almost 200 years ago, to Native Americans walking the Trail of Tears in 1836. Contemporary sightings are typically reported along a stretch of gravel road ominously nicknamed the Devil’s Promenade. While both paranormal and scientific researchers have been working tirelessly to figure out the source of the Hornet Spook Light for years, no definitive conclusions have ever been drawn.

In one of the largest art thefts in history, Boston’s Isabella Gardner Museum was robbed of 13 valuable paintings on 18 March 1990. After successfully subduing the hapless security guards and pretending to ‘arrest’ them, two men disguised as police officers made off with hundreds of millions of dollars’ worth of loot, including works by Vermeer, Rembrandt and Flinck. Despite an extensive investigation into the heist and a substantial reward for the return of the artworks being offered, no one has ever been arrested or charged for the crime. The museum still displays the empty frames of the paintings, in the hope that they will one day find their way back.

It was well known that Jimmy Hoffa, the former Teamsters Labor Union president and a convicted felon, had ties to mobsters and Mafiosos in the US. So when Hoffa went missing on 30 July 1975, the finger pointed in the seemingly obvious direction. The disappearance came just two weeks after a huge sum from the Teamsters largest pension pot was stolen, and on the night that he’d told his family he was meeting with two known members of the mob at a Detroit restaurant. But the pair insisted no such meeting ever took place, and even FBI surveillance couldn’t prove they were lying. With no arrests made and no body recovered, the trail went cold.

In Maya tradition, bird deaths are believed to signal the end of the world. And 31 December 2010 saw around 5,000 red-winged blackbirds rain down from the skies above Beebe, Arkansas, to their instant deaths. The following year, on the same night, another 200 birds plunged to the ground. The 'strong working hypothesis' offered for these mass deaths was the use of illegal New Year’s Eve fireworks, which could have incapacitated the birds with their ear-splitting booms. But there have been another 12 New Year’s Eve celebrations since it last happened, so why isn’t it more common if the fireworks are solely to blame?

Between 1692 and 1693, 20 people were executed as part of the infamous Salem witch trials. Suspicions of witchcraft were first raised when a group of young girls started experiencing violent contortions and screaming fits, attributed to supernatural possession by a local doctor. This triggered a huge witch hunt, resulting in 200 people standing accused. But for over three centuries, the real cause of the girls’ sudden attacks, and therefore the fundamental reason for the witch trials, has been debated. Some blame the hysteria on juvenile delinquency, performative behaviour and boredom, while others have suggested ingesting a hallucinogenic fungus could explain the odd symptoms.

America was stunned on 22 November 1963 when President John F. Kennedy was fatally shot in Dallas, after barely half a term in office. The prime suspect in the assassination, Lee Harvey Oswald, was shockingly murdered himself just two days later, at point-blank range and on live TV by police informant Jack Ruby. Given Oswald’s self-proclaimed Marxist leanings and his previous defection to the Soviet Union, there has always been speculation that there was more to JFK’s murder than what meets the eye. Oswald might have personally fired the gun, but a 2017 poll showed that most Americans believe he didn’t act alone.

The New Jersey Pine Barrens lies at the centre of a dark 18th-century legend pertaining to a woman named Deborah Leeds, who is said to have borne 13 children. But the story goes that her thirteenth came kicking and screaming into the world with cloven hooves and leather wings. After attacking its mortal family, the goat-headed demon is thought to have flown into the Pine Barrens. There have been alleged sightings of it here ever since. Something must have given stock to such a fable – is it a bat? A bird? A vicious rumour designed to tarnish an enemy’s reputation? Perhaps the mystery is more appealing than the potential reality. 

It’s one of the most enduring murder mysteries in the United States. And today, over a century later, still nobody knows whodunnit. The victims were a married couple living in Fall River, Massachusetts, who were butchered with an axe in their home (now a B&B – if you like your weekend breaks with a side order of spooks). Their daughter, 32-year-old Lizzie Borden (pictured), was accused of double homicide in 1892 and later acquitted. But she was nevertheless believed by many to be guilty; shunned by the town and vilified by the rest of the world. Did she really get away with murder? If she did, we’ll ever know.

Coined by New England author and occult researcher Joseph Citro, the ‘Bennington Triangle’ refers to a mysterious area of southwestern Vermont where five people went missing between 1945 and 1950. The most high-profile disappearance was that of Paula Jean Welden in 1946. A sophomore at Bennington College (pictured), Welden told her roommate that she was heading out for a hike. She never returned. With no evidence of foul play, no corpse and no forensic clues, the details of Welden’s disappearance were never pieced together. According to Citro, the Bennington Triangle has a special energy that attracts aliens. Make of that what you will.

During the Watergate scandal of the 1970s, which saw President Richard Nixon forced to resign, a critical gap of 18-and-a-half minutes was discovered in a White House audio recording relating to his involvement. Nixon’s secretary admitted to accidentally erasing five minutes of the taped conversation, which may have been between the president and his chief of staff Bob Haldeman – but who was responsible for the other missing 13 and a half minutes? Possible culprits include the former chief of staff Alexander Haig, who blamed the convenient mishap on a 'sinister force'. And as for what was said, we can only assume somebody didn’t want us to hear it…

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