Going Underground

Jill Heinerth nearly died when she was trapped by ocean currents inside an Antarctic iceberg. She's one of the world's most accomplished underwater cave divers, often exploring caves no one's ever been in, which show her "the veins of the Earth."

Renowned filmmaker Werner Herzog was awe-struck when he saw the Chauvet cave paintings dating back 32,000 years. "You can see clearly that this is the beginning of modern man," he says.