The Oak Island Money Pit
Oak Island is a quiet little rock off the coast of Nova Scotia, Canada, with a very famous sinkhole. When it was discovered in 1795, the Oak Island Money Pit had some obvious signs that it might contain treasure: it was marked with flagstones and there was evidence that someone had used a pick to dig deep into the hole. Whatever maniac originally did this kicked off two centuries of treasure hunting, and indeed, weird stuff has been occasionally found in the pit. Rocks with inscriptions, many layers of oak logs, and maybe even a booby trap. Six people have lost their lives in the excavations, and the sinkhole frustratingly fills with water whenever any headway is made. Whatever is down there — if there is anything down there — was put there by someone with one dickish sense of humor.