If so, then consider Ruby Falls.
The entrance is pictured here - a picture made by Oydman which was posted on Wikipedia.
Ruby Falls is located in the Chattanooga TN area and is very interesting.
We are linking today to 2 very brief write ups about it.
Of course we do disagree with the 200 -400 million year history
But, other than that, this is a site worth visiting.
HERE'S THE LINK to Ruby Falls
And HERE'S THE LINK to what Wikipedia has to say about it
