Underground Marvels
Ireland's Underground Alcatraz (S02E05)
For more than 400 years, hidden military fortresses along the southern coast of Ireland have stood guard against invaders. Now, specialists delve i...
S02E05
Show
Season 2 Episodes
S02E02 - Mystery of the Kentucky Cave
Underground Marvels
S02E03 - Cincinnati's Secret Caverns
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S02E04 - Buried Lab of the Black Hills
Underground Marvels
S02E05 - Ireland's Underground Alcatraz
Underground Marvels
S02E06 - Subterranean Silo Survival
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S02E07 - Italy's Subterranean Secret
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S02E08 - Grand Canyon's Lost Treasure
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S02E09 - Murder Raid Tunnels
Underground Marvels