Florida is home to an underwater cave system that attracts divers, yet this is one of the most dangerous sites in the world.

Her finds tend more to sand dollar fossils. The real treasure, as she hopes the kids understand, is the H 2 O itself. 360° Video: Explore Florida caves in this online experience here.

Devil's Den is an underground spring inside a karst window — a cave formed by the collapse of the ground, exposing the water below. Located 25 miles south of Gainesville, it's one of Florida's ...