The one-hour special Explorer: The Deepest Cave premieres on May 30 at 10/9c on the National Geographic Channel and streaming on Disney+. On a cloudless spring day in southern Mexico, I follow ...

Enter a cohort of maverick scientists who strap on a harness and oftentimes scuba gear, and delve deep into the belly of the Earth. Who are these cave explorers, what have they found, and what do ...