Mary (Marie) Celeste
A ghostly ship, found abandoned in the middle of the Atlantic, still seaworthy and intact but with its crew seemingly having vanished into thin air is a staple of mystery books. Most tales feature the Marie Celeste, found with sails set, food still on plates in the galley, tea still warming on the stove, the captain's log showing no signs of anything untoward and the sea calm all around. Its name is a byword for mysterious happenings at sea. The truth is, there really was a mysterious abandoned ship, though called the Mary Celeste, and in 1872 it was spotted drifting between the Azores and Gibraltar, on route from New York to Genoa with a cargo of grain alcohol stored in barrels. When the ship was boarded, the 8-man crew were nowhere to be seen and the sails, partly set, were in a poor condition, some missing altogether. Much of the rigging was damaged, with ropes hanging loosely over the sides, one long rope - the main halyard - trailing behind the ship. Some of the hatch covers over the hold were removed, and the lifeboat was missing; as was the captain's navigation equipment. The cabins were untidy and wet from water coming from the open hatches and there was several feet of water in the hold. The galley however, was tidy and with plenty of provisions.
The last log entry was 9 days earlier recording its position 400 miles to the west. There were no obvious signs of fire or violence; the evidence indicated an orderly departure from the ship using the missing lifeboat, but no real evidence of why. The Ship was brought into Gibraltar and in the ensuing enquiry 9 of the barrels of alcohol were found empty. Most of the official investigations suspected that the crew got drunk and mutinied though there was no other evidence for this supposition other than xenophobic attitudes toward the four general seamen who were German whilst the Captain, two officers and steward American. It is likely the ship would have been forgotten if Arthur Conan Doyle (of Sherlock Holmes fame) had not written a short story in 1884 fictionalising an account of the the 'Marie' Celeste, changing several details and adding the tropes we know so well today. It was his version that became the mystery; fact and fiction creating differing accounts that mystery-mongers try to 'solve', usually with more and more outlandish explanations such as waterspouts, seaquakes, icebergs, giant squids, alien abduction and many more.
Though we will likely never know what exactly happened in 1872 off the Azores, the most likely explanation is based around the fact that the empty barrels were made of a different oak than the others and were porous. This meant the alcohol would have seeped through the wood and evaporated in the hot close air of the hold. As the resulting vapour is heavier than air it would accumulate inside the ship. The captain fearing an explosion - experiments have shown that a small non violent explosion was possible and if that happened may have scared the crew into thinking it was about to explode violently - vented the hold and temporarily abandoned ship in haste to the safety of the lifeboat. But the tow line connecting the small boat to the ship became loose and the crew, unable to keep up with the part-rigged ship, were lost in the vastness of the Atlantic ocean. The Mary Celeste was then found 9 days later, the alcohol having evaporated and the ship mysteriously abandoned.