Part of Ozark National Forest, this cave, filled with flowstones, rimstone terraces and underground rivers, is among the most beautiful of America's cave systems. A guided tour (1hr; offered all year) of the .4mi Dripstone Trail covers the older part of the caverns (240ft deep) and takes in the 1,150ft-long Cathedral Room. The more challenging 1.2mi Discovery Trail tour (1 1/2hrs; offered only in summer) passes through a younger, deeper system (366ft deep) and requires visitors to navigate 700 steps.