This past Memorial Day weekend we went down to Chattanooga,TN. On the way there we stopped at a fun place called Ruby Falls. We took an elevator down a ways into the ground and then walked for a while underground to get to a really tall underground waterfall.
It was really neat to see all the different formations, the one in the picture above is called the chandelier.
They had little lights hidden in the rocks throughout the whole cave to help us see where we were walking and to highlight certain formations, then when we got to the waterfall they had a light show. It was amazing to be underground and see this huge waterfall coming from, what looked like, out of nowhere.