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Secrets of the Underground is available on Discovery+ in the following countries:

Austria

Germany

United Kingdom

Ireland

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Secrets of the Underground (2017)

⭐ 4.3/10

3 votes

2 Seasons 16 Episodes

Genres

Reality

Documentary

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.

IMDb + Watchlist