On a Sunday morning in 1942 a US Navy blimp drifted out of the fog and settled onto a California street. The radio worked, the parachutes were stowed, the doors stood open. The two officers who had flown it were gone, and they have never been found.

Herodotus wrote that a Persian army marched into Egypt's Western Desert to burn an oracle and was buried alive by a sandstorm while eating lunch. Twenty-five centuries later, not one confirmed soldier of that army has ever been found. Two rival claims say they solved it, and most Egyptologists accept neither.

In 1912 a four-year-old walked away from a Louisiana swamp and vanished. Eight months later a boy was found on the road with a traveling handyman, and two mothers stood up to claim him. A court chose one of them. Ninety-two years later a DNA test proved the court had chosen wrong.

She was writing confessional singer-songwriter music in New York years before anyone called it that, and almost nobody heard it. In August 1974 she wrote a handful of calm farewell letters, packed her Volkswagen and drove out of Ann Arbor. Neither Connie Converse nor her car has ever been found.

On the morning he was due to fly to America, the lyricist of the Manic Street Preachers checked out of a London hotel and drove west, leaving his passport behind. Two weeks later his car turned up at a service station beside the Severn Bridge, battery flat, family photographs on the seat. Britain has been arguing about the rest for thirty-one years.

A crashed car on a dark New Hampshire highway. A bus driver who offered help and was turned away. Nineteen minutes later the police arrived and the driver was gone. Twenty-two years on, her phone and bank cards have never registered anywhere on earth.

She was nine years old, and at half past two in the morning she dressed, packed a bag and walked out into the rain. Drivers saw her on the highway; when one turned back she ran into the trees. A year and a half later her bag was dug up twenty-six miles away, wrapped in plastic and buried.

In April 1848 seven men, seven horses, twenty mules and fifty bullocks left the last cattle station on the Darling Downs and headed west into unmapped country. Not one of them was ever seen again. After more than a century of searching, the only object ever tied to them by name is a small brass plate stamped Ludwig Leichhardt 1848.

On a hot July morning in 2014, a German holidaymaker walked into an airport doctor's office in Bulgaria, went white, dropped his bag and bolted. Security cameras followed him over a fence, across a meadow and towards a line of trees. His wallet, phone and passport are still evidence, and he has never been seen again.

At lunchtime on a summer Sunday, the leader of a nation swam out from a beach he loved and never came back. Australia mounted one of the largest searches in its history and recovered nothing at all. Thirty eight years later a coroner finally said what had happened, and the rumours carried on anyway.

A Dutch artist left Cape Cod alone in a boat twelve and a half feet long, bound for England, as the middle chapter of a work titled In Search of the Miraculous. Radio contact stopped after three weeks. Nine months later a Spanish trawler found his empty boat drifting off Ireland, and then even the boat vanished.

Enrico Fermi placed him in the category of Galileo and Newton. In March 1938 Ettore Majorana withdrew his money, took his passport, wrote two farewell letters, cancelled them by telegram the next day, boarded the night ferry from Palermo to Naples and was never seen again. Italian prosecutors did not close the file until 2015.