Mammoth Cave is one of the seven natural wonders of the world and is located about 80 milse south of Louisville, Ky. There are over 350 miles of cave that have been mapped and they think there are at least double that which haven't been mapped yet.
This is the original opening to the cave, which has been open to tourist since the late 1800's. They have several other manmade openings so all the tours aren't so long of a walk. The constant temperature in the cave is 54 degrees year round.
There are many stalagtites (down from ceiling) and stalagmites (up from floor) to be seen on any of many tour choices. The tours are all walking tours and are up and down stairways and paths. Even thought if's cool in the cave, it's easy to work up a sweat during your tour.
