Oak Island, one of over 300 islands in Mahone Bay on Nova Scotia's Atlantic coast, is about 1.6 km long and 0.8 km wide. It is reputed by legend to be the site of buried treasure, the loot being attributed to various pirates, including William Kidd, Henry Morgan and Blackbeard, as well as to Inca refugees fleeing from Spanish conquistadors in South America.

In 1795, 16-year-old Daniel McGinnis discovered a depression in the ground near a huge oak tree and evidence that a block and tackle had been used there. McGinnis and 2 friends dug at the site, revealing a filled-in shaft with platforms of decayed oak logs at 3 m levels. They quit digging after 9 m, but in 1804 returned and reached the 30 m level before the shaft filled up with salt water.

Subsequent digs uncovered tunnels connecting the "money pit" with the ocean. A dam built to solve the problem was destroyed in a storm. Vast sums of money have since been spent in excavations that have cratered the island, and 4 treasure hunters died in an accident in 1965. Though no treasure has been found, a submarine TV camera, lowered into a cavity 60 m below the surface in 1971, produced faint images of what is thought to be 3 chests, a pick and a dismembered human hand.