Ruby Falls is the tallest underground waterfall open to the public in the United States. Ride a glass-front elevator 260 feet into Lookout Mountain and follow a guided cavern trail to the waterfall. The Incline Railway is a historic passenger railway that climbs Lookout Mountain at one of the steepest angles in the world, offering expansive views of Chattanooga from the summit. Rock City is a mountaintop attraction featuring walking trails, gardens, and overlooks with wide-ranging views of the surrounding area.