Deep South

Stephen Alvarez

Rumbling Falls Cave
Tennessee

Far from the light of day, cavers illuminate the four-acre, 350-foot-high Rumble Room. Reaching the limestone cavern entails dropping down a 68-foot shaft, climbing up two 14-foot waterfalls, and stooping or crawling along 2,000 feet of passageways, some barely a foot wide.

This month on: National Geographic