Ruby Falls is not only the deepest underground waterfall in the United States, but it is also the highest waterfall underground.

Ruby Falls is a 145-foot waterfall located inside Lookout Mountain.. The entrance to this underground wonderland looks like a European castle.

The Falls are 26 stories deep inside Lookout Mountain. There is an elevator that transports guests down to the cavern trail. The path is about a mile walk roundtrip.

Be sure to wear good shoes when you visit. The ground may be naturally slippery in spots.

If you visit during the summer, you might want to bring a light sweater. The temperature inside the cave is around 60 degrees all year long.

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