Alabama's "Coolest" Underground Adventure. Travel 1.3 miles thru one of the largest show caves in the U.S. Marvel over the huge opening leading into the cave, experience the beauty of the stalagmite formations, hear the gurgling sound of water from Mystery River. See a prehistoric shark's tooth embedded in the ceiling and look closely for the bats scattered throughout. Archaeological excavations by the University of Alabama State Museum of Natural History and the Archaeological Resource Laboratory at Jacksonville State University have indicated early occupation by Native Americans.