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National Geographic Documentaries
Into the Lost Crystal Caves
TV-PG
2010 • E39 Oct 9, 2010 45mNGC goes inside one of the greatest natural marvels on the planet - a giant crystal cave described as Superman's fortress, with magnificent crystals up to 36 feet long and weighing 55 tons. A team of experts venture into the cavern, enduring scorching-hot temperatures that could kill a human after just 15 minutes of exposure. They'll push the boundaries of physical limitation to explore a crevasse that could lead to another - and perhaps more spectacular - crystal cave.