Ruby Falls, An Underground Waterfall in Tennessee

Approximately 1,120 feet below ground within the heart of Lookout Mountain near Chattanooga, Tennessee, lies the United States’ tallest and deepest waterfall. Named Ruby Falls, after the founder’s wife, the waterfall is located at the end of the main passage of Ruby Falls Cave, in a large vertical shaft that was eroded out of limestone rock by salt water millions of years ago. The stream, fed by rainwater and natural springs, falls 145 feet and collects into a pool in the cave floor and then continues through the mountain until finally joining the Tennessee River at the base of Lookout Mountain. Ruby Falls is believed to be 30 million years old.