Season 1
Episode 1 - Secrets of the Underground Season 1 Episode 1 Episode 2 - Secrets of the Underground Season 1 Episode 2 Episode 3 - Secrets of the Underground Season 1 Episode 3 Episode 4 - Secrets of the Underground Season 1 Episode 4 Episode 5 - Secrets of the Underground Season 1 Episode 5 Episode 6 - Secrets of the Underground Season 1 Episode 6 Episode 7 - Secrets of the Underground Season 1 Episode 7 Episode 8 - Secrets of the Underground Season 1 Episode 8
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.