Similar to what you see at the more famous Luray Caverns in Virginia, Crystal Grottoes has more formations per square foot than any cave discovered so far. It is also the most naturally kept cave in the world. Don't forget- its 54 degrees in the caves all year round, so it's cool in the summer, and warm in the winter.

From Crystal Grottoes website:

The Crystal Grottoes Caverns were formed in a syncline, or a downward sloping fold in the earth. This downward sloping fold is created when several rock layers are compressed and pushed together much like you would see with folds in a carpet that gets pushed together. In this case, the syncline, which is shaped like a dish with rock on either side, is made up of solid limestone running down 1200 to 1500 feet. During periods of frequent rain the faults fill up with ground water that has picked up carbon dioxide molecules both from the air and decaying plant matter. This process of dissolving out the cave through a solution is very different from the process where some caves form by moving water washing away the rock.