Oak Island — The Money Pit

According to the traditional account, in 1795 three teenagers exploring Oak Island in Mahone Bay discovered a circular depression in the ground beneath an old ship's tackle block hanging from a tree, and began digging. They reportedly found layers of log platforms at regular ten-foot intervals as they descended — a pattern that subsequent excavations claimed to confirm to depths of over 30 metres. Later expeditions reported a network of "flood tunnels" apparently engineered to connect the pit to the sea, flooding it with seawater whenever digging passed a certain depth, an obstacle that has defeated every attempt to reach the bottom of what came to be called the Money Pit.

Six people have died during excavation attempts since 1861. Proposed explanations for what, if anything, lies below range from pirate treasure associated with Captain Kidd, to the lost jewels of Marie Antoinette, to manuscript evidence that William Shakespeare's plays were written by Francis Bacon, to the Holy Grail or the Ark of the Covenant — theories that have sustained more than two centuries of excavation, including the long-running television series The Curse of Oak Island. Geologists note that Oak Island sits on a bed of gypsum riddled with natural sinkholes and underground voids, and argue that the "flood tunnels" and the original depression may be entirely natural karst features that early treasure hunters mistook for engineering — though no investigation has yet definitively settled the question either way.