Bermuda Triangle: A region in the North Atlantic Ocean where numerous ships and aircraft are said to have disappeared under mysterious circumstances.
Voynich Manuscript: An illustrated codex written in an unknown script and language, dating back to the early 15th century, which has defied all attempts at decipherment.
Mary Celeste: An American merchant ship found adrift and abandoned in the Atlantic Ocean in 1872, with its crew missing under puzzling circumstances.
Dyatlov Pass Incident: The unexplained deaths of nine hikers in the Ural Mountains, Soviet Union, in 1959, with injuries and circumstances suggesting a sudden and violent event.
DB Cooper Hijacking: The unsolved 1971 hijacking of a Boeing 727 aircraft by an unidentified man who extorted a ransom and then parachuted out over the Pacific Northwest, never to be found.
The Wow! Signal: A strong radio signal detected in 1977 from space that has not been satisfactorily explained and has not been detected again.
The Lost Colony of Roanoke: A group of early English settlers in North Carolina who disappeared without a trace sometime between 1587 and 1590, leaving behind only the word "Croatoan" carved into a tree.
Jack the Ripper: The unidentified serial killer who terrorized the Whitechapel district of London in 1888, brutally murdering at least five women and evading capture.
The Taos Hum: A low-frequency humming noise reported by residents of Taos, New Mexico, since the early 1990s, with no identifiable source despite extensive investigation.