Hang Son Doong, Phong Nha Ke Bang National Park, Vietnam (@ Carsten Peter/Getty Images)
- This intrepid explorer is somewhat dwarfed by the biggest cave in the world.""Where is our tiny adventurer?
- The 1991 discovery of this system was compared to “finding a previously unknown Mount Everest.”""It does look rather hard to miss
- The largest chamber here is more than five km long, 200m high and 150m wide.""What\s that light at the end of the tunnel?
- Getting lost is a very real (and constant) danger around here.""Surely someone brought a map?