Verëvkina Cave in Abkhazia, the deepest known cave in the world, reaching 2212 m deep.

Is that the end of the cave at the very bottom, or is it just the level wehere water starts and it could be possibly deeper?

Instant claustrophobia when i think about this

This is crazy stuff. I wish there was a documentary made about these people, who seemingly lack any sense of self preservation :D