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.
8 episodes · February 14, 2017
You can stream Secrets of the Underground on Philo, Discovery+ Amazon Channel and Discovery +. It is also available to rent or buy on Amazon Video, Apple TV Store, Google Play Movies and Fandango At Home.
No — Secrets of the Underground has ended.
Secrets of the Underground has 2 seasons and 16 episodes, and first aired in 2017.
Secrets of the Underground holds an average rating of 5.4/10 on TMDB, and it lands best with fans of documentary and reality. Join the discussion below to add your take.
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