8 episodes
First episode: E1
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.
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8 episodes
First episode: E1Show FAQ
Quick answers about this series, release status, and episode totals.
When did Secrets of the Underground first air?
Secrets of the Underground first aired on February 14, 2017.
How many seasons and episodes does Secrets of the Underground have?
Secrets of the Underground currently has 2 seasons and 16 episodes.
When is the next episode of Secrets of the Underground?
Secrets of the Underground is ended, and no upcoming episode is currently scheduled.