Priceless magazine
Most extreme sports leave some margin for error. A climber can turn back a hundred metres from the summit. A big-wave surfer who wipes out can be pulled from the water by a jet-ski waiting nearby. Cave diving offers no such second chances. Go deep enough into the wrong passage, and the only thing standing between a diver and never being found again is a single thin line he laid down himself, and his own discipline in following it back.
