Mammoth Cave the world’s longest cave system
It’s often said that the Age of Exploration is over. Mount Everest has been scaled, Antarctica traversed, every inch of every vast desert or rainforest mapped with satellite imagery and laser ranging technology. Modern-day explorers must look to other frontiers not yet mapped in any atlas:
The bottom of the sea, for example, or faraway Mars. But sometimes we forget another unmapped mystery, often nearer at hand: subterranean caves.