In 1905, a 13-year-old boy, Ben Sands, stumbled upon a remarkable discovery deep within the Craighead Caverns in Tennessee.

Guests board glass-bottom boats to tour the Lost Sea in Sweetwater, Tenn. The Lost Sea is the world's second-largest underground ... is part of a system of caves called Craighead Caverns, named ...

Carlsbad Caverns ... underground lake that holds the title of America's largest subterranean body of water. Visitors can embark on guided tours that take them through the caverns, culminating in a ...

Those craving more depth can follow the Historic Tour through ... Tennessee, Craighead Caverns holds a lake stretching over 4.5 acres—America’s largest underground lake and the second largest ...