In 1910 a singer vanished from her home in London, and her husband said she had gone to America. A detective believed him, until the husband ran. What followed was the first manhunt in history to be decided by a message sent through the air.

On a hot morning in August 1892, Andrew and Abby Borden were killed with a hatchet inside their own home in Fall River, Massachusetts. Their daughter Lizzie Borden was arrested, tried and acquitted - and the case was never solved.

A man knocked down a wall in his basement in 1963 and opened a hidden city cut 85 m into volcanic rock, big enough for 20,000 people. Sixty years later, archaeologists still cannot say who dug the first tunnels.

In January 1931 a stranger left a message sending an insurance agent to an address that did not exist. When he came home, his wife lay dead in the parlour. He was sentenced to hang, then freed, and the Wallace case has never been solved.

Cold War navy microphones on the Pacific sea bed picked up a whale singing at the wrong pitch. Scientists have tracked it across an ocean for decades. Nobody has ever identified the animal making the sound.

Between 1918 and 1919 someone broke into the homes of Italian grocers in New Orleans at night and attacked the sleeping families with their own axes. The police arrested the wrong people, a letter promised to spare every house playing jazz, and the Axeman of New Orleans was never identified.

In 1964 a survey party landed on the one flat ledge of Bouvet Island and found an open boat with no markings, and a pair of oars laid out on the rock 90 m away. No people, no camp, no bodies. Two years later the boat was gone.

Between 1912 and 1914 three brides drowned in their baths, in three towns, with three verdicts of accident. Nobody connected them until a grieving father opened a Sunday paper and recognised the shape of his daughter's death.

In January 1947 a 22-year-old woman was found dead in an empty lot in Los Angeles. The newspapers called her the Black Dahlia. 750 investigators, 500 false confessions and 79 years later, nobody has ever been charged.

In 1898 a Swedish farmer in Minnesota pulled a stone from the roots of a tree. It claimed Norse explorers reached the heart of America in 1362. The experts called it a fake within months. Nobody has ever proven who carved it.

In 1983 a 16-year-old walked to her boyfriend's house in an English village and never arrived. Her murder was the first case ever shown on Crimewatch. 25 years later, a traffic stop of a young man not yet born in 1983 gave the police a name.

In the autumn of 1888, 5 women were murdered in the poorest streets of London. 2,000 people were questioned, 300 were investigated, and the man the newspapers called Jack the Ripper was never caught.

In 1965 a fireball seen in 6 states lit the sky, and soldiers sealed a wood in a small Pennsylvania village. The newspaper said an object had fallen. By the next edition, nothing had been found.

In December 1946 an 18-year-old student walked up a Vermont mountain trail in daylight, was seen by several people, and vanished. Hundreds searched. They found nothing at all.

The biggest manhunt Britain had ever mounted spent 18 months chasing a man who did not exist. It took 26 years and a scrap of dried envelope glue to find out who invented him.

In 1992 Rachel Nickell was killed in broad daylight on a London common while her 2-year-old son watched. For 16 years the police chased the wrong man - while the real killer was already in their files.

Something destroyed 4 square km of a walled capital in a single instant and was heard 150 km away. 400 years later, historians still cannot say what it was.

A cargo ship found a small racing yacht drifting with nobody aboard, and 3 logbooks on the table that explained everything except the one thing that mattered.

Several hundred slabs carrying the same strange message are pressed into the roads of two continents. The method is understood. The hand behind it is not.

500 children arrived for a marching band competition. Within hours, 259 people were in hospital and nobody could say why. Forty-six years later the official file still blames fear, and the babies who collapsed have never been explained.

The Inca ran an empire of millions without writing a single letter. They used knotted cords instead. We cracked the numbers a century ago, and everything else on those cords has resisted us ever since.

A 222 metre ship with 29 men aboard vanished from another vessel's radar in a November storm. There was no distress call and no survivor. Fifty years and two official inquiries later, nobody agrees on what sank her.

The same female DNA turned up at 40 crime scenes in three countries, including the murder of a young policewoman. Hundreds of officers hunted her for years. Then one impossible test result revealed where she had really come from.

A police constable signed a statement saying she watched a chair slide across a council house floor with nobody near it. What followed was the most heavily recorded haunting in British history, and the most heavily disputed.

A man calling himself R.C. Christian walked into a Georgia granite yard in 1979, ordered a 108 tonne monument in eight languages, and vanished. In 2022 somebody blew it up. Both men are still unidentified.

On 11 June 1962 three prisoners left dummy heads in their beds and paddled into San Francisco Bay on a raft made of stolen raincoats. Sixty-four years later nobody can say whether they drowned or landed.

Two women left a house in Lancaster in September 1935 and were next seen as parcels in a Dumfriesshire stream. The killer had removed everything that identifies a body. Then a team of anatomists put the bodies back together.

Four young people drove to an abandoned munitions plant in West Virginia in November 1966 and came back to town badly frightened. More than a hundred sightings followed. Then a bridge fell, and the story changed shape forever.

A landlady in Florida found the doorknob too hot to hold. Inside, a 67-year-old woman had been reduced to ash in an armchair, while the room around her was barely touched. The police chief wrote to J. Edgar Hoover for help.

In August 1955, eleven people fled a Kentucky farmhouse and told the police that small silver figures had besieged them all evening. Twenty officers searched the property. They found bullet holes, torn screens and no explanation.

A hunter found a steel drum in the New Hampshire woods in 1985. Inside were a woman and a child. It took four decades, a new science and a librarian's hunch to give all four victims their names back.

On Valentine's night 1988 a twenty-year-old woman was stabbed to death in a flat above a Cardiff betting shop. Three innocent men went to prison for it. The man who did it lived quietly two miles away for fifteen years, until a scientist scraped back the layers of paint on a skirting board.

On a freezing December afternoon in 1944 the most famous bandleader in the world climbed into a small single-engine aircraft at a Bedfordshire airfield and flew towards France. No wreckage, no bodies and no crash site have ever been found, and the argument over why is still running eighty years later.

In 2000 a gilded mummy surfaced in the Pakistani desert with a cuneiform breastplate calling her the daughter of King Xerxes. Two governments claimed her. Then a curator in Karachi worked out that she had died in about 1996, with a broken neck, and that nobody knows who she was.

In 1994 a German archaeologist walked onto a low mound in southeastern Turkey that everyone else had written off as a medieval graveyard. Under his feet lay carved stone circles raised by hunter-gatherers eleven and a half thousand years ago, and nobody can agree what they were for.

A fifteen-year-old took a shortcut home in 1983. The investigation that followed produced the world's first DNA exoneration, the first DNA murder conviction, and a mass screening that never found the man who did it.

Three men sailed out of Airlie Beach one autumn morning. Five days later their boat was found drifting 88 miles offshore, engine idling, food on the table, and nobody aboard.