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.
Returning Series
Secrets of the Underground
February 14, 2017
December 16, 2017
2
16
English
Science Channel
Science
Millions of dollars of stolen Gold Rush treasure is rumored to have been stashed in a cave in Northern California. Rob Nelson and Stefan Burns use cutting-edge technology to search for the legendary treasure.