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6 Seasons
S4 E3 12/14/19

Wonders of the Underworld

New discoveries reveal various deserted, underworld engineering projects -- from a terrifying sea fortress to a strange complex of towers in a forest of ice. Experts explain why they were built and why they were eventually abandoned.

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Discovery Exploration

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Secret of Supervillain Island

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Escobar's Castle

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Labyrinth of the Dead

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Pompeii's Gate to Hell

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