No this is not Sci-Fi

This is an actual cave in Mexico, only recently discovered in 2000. It was a veritable crystal factory for tens of thousands of years, sitting under just the right conditions of mineral filled water, heat and time until the 1980s when a mining company accidentally drained the cave. If these crystals look huge, its because they are the biggest on Earth. Some of them weigh in at over 50 tons. Because the mining company drained the cave they have to be extremely careful about who goes in there. The lack of water, introduction of other natural gases and air temp can all effect the crystals, possibly causing them to collapse. So for now, marvel at the photos and check the story from National Geographic about the authors trip into the stifling cave.