Hamilton Pool Preserve, in Austin, Texas, was created quite naturally when the dome of an underground cave collapsed revealing this stunning natural pool. It is now frequented by day-trippers and naturalists. That's naturalists not naturists, although no doubt someone has tried to go skinny dipping at one point!
Stalagtites adorn the roof of Luray Caverns, Virginia, the still waters throwing a perfect reflection.
Legend has it that early cavemen inhabited Wookey Caves in Somerset, England.
This underground lake in Mellisani Caves, near Kefalonia, was found when the roof of the cave collapsed after an earthquake in 1953.
This underground lake near Macan Ché on the Yucatán Peninsula is one of many that are considered to be gifts from the gods by the Mayans, and therefore sacred.09 Sanghavedanta
The limestone flow feeding into this underground lake in Mexico resembles a waterfall turned to stone. Maybe the Ice Queen is privy to this particular cavern?
How long must it have taken for this little waterfall in Banff, Canada, to make this underwater lake?