Underwater Cairn
In 2003, Israeli scientists found a huge stone structure in the Sea of Galilee. It’s estimated to weight 60,000 tons and be 32 feet high. No one knows what it does or why it’s there or who put it there. They speculate it could be marks for burials. It’s also possible that it was above ground at some point, but was submerged underwater as sea levels rose. It could be as old as 4,000 years old.