Bushman's Hole, on the edge of the Kalahari Desert in South Africa, is one of the strangest places on Earth. It's a prehistoric crater on an otherwise endless track of desert, and for an elite but extreme fraternity of explorers, what happened there is the stuff of myth and legend.
The terrible beauty of the place can't be seen from the air, or even the ground. But if you trace the walls down, you reach a tiny pool covered in algae. Keep going, through a narrow shaft running for another 150...Full Story