Many of the world's most mysterious abandoned buildings are hidden underwater and underground. But now, experts use cutting-edge tech to reveal the secrets of these strange places and finally explain why they were deserted. The segments of this special come from various episodes. |
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Title: | Secrets of the Abyss | |
Air Date: | December 19, 2019 | |
Runtime: | 60 min | |
Genres: | Mystery History Travel | |
Alien : Contains spoilers. Click to show. oops!