On a clear winter morning in 1909 a brand new liner overtook a cargo steamer off the coast of South Africa, exchanged polite signals, and pulled ahead. Nobody has seen her since, and after a century of searching not one plank has ever been recovered.

Abandoned in the Arctic ice in 1931, the crewless SS Baychimo went on sailing by herself for nearly four decades - sighted, boarded, stripped of furniture and a whaleboat, and lost again, until she vanished for good.

January 1921: a five-masted schooner hard aground on Diamond Shoals, sails set, dinner mid-preparation — and eleven men gone without a trace. Five federal departments investigated. None could explain it.

In November 1955 the MV Joyita was found half-submerged and drifting in the South Pacific, five weeks overdue, her radio tuned to the distress frequency and a doctor's bag of bloodstained bandages on deck. Her cork-lined hull made her almost unsinkable. So why did all 25 aboard abandon her — and where did they go?

In March 1918 a massive US Navy collier sailed from Barbados toward Baltimore and dissolved into the Atlantic. No SOS, no wreckage, no bodies — the Navy's greatest non-combat loss remains unexplained.

A desperate distress call, a crew found frozen in terror, a ship that exploded before it could be towed — and not a single registry on Earth that says the vessel ever existed.