Secrets of the Underground
A search for an underground escape route said to have been used by Al Capone. Also: who or what built earthen mounds in Washington state.
6. Mystery of the Ice Cave
0.0Dec 2, 2017 · 60 min
A strange cave freezes in the summer and melts in the winter, and a massive sand dune swallows a small child in an instant. Rob Nelson and Stefan Burns use cutting-edge technology to investigate these mysteries of the natural world.