Devil's Den in Florida is a karst spring, a kind of short cave with a sump at the end. Devil's Den is a popular Florida vacation destination, and is used commercially by cave divers. The owners have widened the cave entrance, built a path to the sump and constructed a diving platform with a wooden stair into the water. The entrance hall of the cave is reached through a relatively narrow passageway to a titanic limestone chamber dripping with green vines and a wide hole in the ceiling.

The spring and cave are open to all divers with open-water diver certification. Devil's Den is a favorite among training spot for scuba instructors in the United States. Because it offers access to the surface at all times, it is a perfect place to enjoy the thrill of cave diving without the actual danger.