Watch Into the Lost Crystal Caves full movie online Movies123. Watch Into the Lost Crystal Caves 123movies online for free. Into the Lost Crystal Caves 123Movies: NGC 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.