Morgan O’Hanlon: As you’re driving through West Texas and through Balmorhea, this kind of big open desert, you get to the Phantom Springs Cave and it’s this tiny little narrow crevice.

Ellison's Cave in Georgia is the deepest cave in the state and features the deepest unobstructed pit in the continental ...

Beneath the Earth’s surface lies a world so extreme and isolated that it seems more like an alien planet than part of our own. Veryovkina Cave, the deepest known cave on Earth, plunges a staggering ...