Much of the underground world is carved by nature; many of its greatest treasures are the result of elemental processes as old as the planet itself. We haven't been slow to make use of these extraordinary and dramatic spaces - they provide us with a record of our earliest history, if we know where to look. But it's a dangerous, often threatening realm, with its dark caverns, narrow environments and rushing water. Far from the light of day we join intrepid underground explorers as they push back the boundaries, make amazing discoveries and share sights of remarkable beauty.
Episode #101 / Length: 56 minutes
