Ruby Falls Cave has all the geological features one would expect (stalactites, stalagmites, etc.) with one magical addition: an underground waterfall. Until humans tunneled into the cave in the 19th century, the water had been trickling undiscovered beneath Tennessee for roughly 200 million years.
The cave system, called Lookout Mountain Caverns, had been used for shelter as far back as the Civil War, likely even earlier. But when a railroad was built to intersect with the caves, they were sealed shut. It wasn’t until amateur spelunker Leo Lambert tunneled higher up the mountainside to reopen the caverns that the underground waterfall was exposed to the light of day.
Lambert named the falls for his wife, Ruby, and opened them to the public. They became a popular tourist destination, advertised across the South on barns painted with the slogan “See Ruby Falls.” The caves and the underground waterfall were some of the first such attractions to be electrically lit. The light display continues to wow visitors, as its hues melt into one another on the cavern walls.