12/14/1926 Agatha Christie's real life mystery ends

December 14, 1926.  Agatha Christie was already a bestselling author in 1926 when she disappeared, leaving her daughter at home, and her car beside a lake.  The exact nature of her problem is still debated, but it appears to have been a nervous breakdown brought on by stress.  Her husband had recently asked for a divorce and that day, after an argument, had gone off to spend the weekend with his mistress.

Christie was found on December 14 in a hotel in Yorkshire, checked in under the last name of her husband's mistress.  In her autobiography, she skipped the entire event.  So the mystery ended, but you can't exactly say it was solved.