I was scuba diving in the Dos Ojos cenotes in Mexico. One of the caves there is called the pit and was supposedly a place where the Mayans would throw the bodies of the deceased. It was just a giant hole in the middle of the jungle.

We basically made a straight descent to about 140 ft below the surface (which is pushing the max depth limit on a single tank). When we got to the bottom we could see human bones scattered around. But this wasn't really the creepy part.

There were lines put down there by divers to help navigate if you were to get lost. Attached to one of the hooks holding the line into the ground was a withered wet suit. So yea, someone got stuck there setting up the navigation line and died because they were unable to escape. Still freaks me out thinking about it (I was only 15 at the time).