Ruby Falls is a 145-foot high underground waterfall located within Lookout Mountain, near Chattanooga, Tennessee I've seen this waterfall in person. My family would travel to Ruby Falls every year for at least 5 years starting when I was about 7 or 8 years old. It's looks just as gorgeous in person as it does in this photograph. This another favorite waterfall of mine because it's in a cave. And it helps when they put the purple and blue lightening against the falling water.