(via MinuteEarth) Krubera Cave, one of our planet’s deepest known caves, extends 2200 meters into the earth – that’s a depth of nearly six Empire State Buildings. Or at least, that's as far down as ...

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 ...