The Mary Celeste
The story of the Mary Celeste is widely considered the greatest maritime mystery of all time. On December 4, 1872, the ship was discovered floating in the middle of the Atlantic Ocean. The crew had simply vanished. The ship had sustained no damage, was not at risk of sinking, and was stocked with food and supplies. The lifeboat was missing, but there's no indication of why the crew would jump ship, never to be heard of again.
That's the mystery most associated with ole Mary, but make no mistake: the Mary Celeste was had a freaky reputation even before she made 10 sailors disappear without a trace. In fact, Mary Celeste wasn't even her first name — she was originally the Amazon, but had to be rebranded after three captains died aboard the ship, and random fires broke out. After she was discovered abandoned in the ocean, she was acquired by an insurance fraudster and deliberately run aground in Haiti (the wreck was discovered in 2001). It's probably for the best that she was taken out of commission, because for whatever reason, she really seemed to have it in for people.