Ruby Falls is a stunning underground waterfall located within Lookout Mountain in Chattanooga, Tennessee. It is one of the tallest and most-visited underground waterfalls in the United States, plunging 145 feet into a deep pool below. Visitors can take a guided tour through the cave system to reach the falls and learn about the geological formations and history of the area. The colorful lighting enhances the beauty of the waterfall, creating a magical and unforgettable experience for all who visit.