Weeki Wachee, Florida, United States

Eagle's Nest Sinkhole

Eagle's Nest is a deep freshwater sinkhole in the Chassahowitzka Wildlife Management Area near Weeki Wachee in west-central Florida. From the surface it appears as an unremarkable, lily-fringed pond perhaps 30 metres across; below the surface, the pond drops into an immense karst cavern called the Ballroom, with a flat ceiling at 18 metres and a sand floor at 65 metres. From the Ballroom, two side tunnels (Main Cavern and South Tunnel) descend to 95 metres or more along surveyed lines. The site has been dubbed 'the Mount Everest of cave diving' and is also notorious for fatal accidents involving untrained divers; access requires full-cave certification, deep-mix training, redundant rebreathers or doubles, and registration. The water is gin-clear at 22 C constant. There is no surface marine life of note, but the geology is staggering: a complete karst cathedral hidden beneath a Florida pine forest. Florida regulations require certification verification at the gate.