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Secrets of the Underground
2017
Published on, 3 months ago
Secrets of the Underground
Mystery of the Serpent Mound 1 Season 2 Episode
60 min
2017
4.3
Rob Nelson explores mysterious tunnels beneath Denver's airport and capitol building to investigate rumors of a secret organization operating below. In Ohio, he tries to uncover the ancient secrets of a mound shaped like a serpent.
