In 2009, 26-year-old John Edward Jones became trapped in Nutty Putty Cave, a narrow, twisting cave system near Salt Lake City, Utah.
While exploring with family, he got stuck in an uncharted passage just 10 inches wide and 18 inches high, headfirst and upside down.
Despite intense rescue efforts over 27 hours, the position and terrain made it impossible to free him. He died in the cave, and it was permanently sealed with his body inside.