When did Underground Marvels Season 2 Episode 1 air?
Underground Marvels Season 2 Episode 1 aired on August 5, 2021.


Historians, engineers, and experts take a look at the underground structures, systems, and phenomena that exist beneath our feet.

The top-secret construction of a massive nuclear bunker remained concealed under a palatial West Virginia hotel for decades, and now, experts reveal how this vast subterranean structure was one of the most closely guarded Cold War secrets in US history.
Direct answers for episode-level questions and details.
Underground Marvels Season 2 Episode 1 aired on August 5, 2021.
This episode runs for approximately 45 minutes.
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