7. Naica Mine, Mexico
Discovered back in 2000, this limestone cave filled with glistening crystal beams is as big as a football field and as high as a two story building. Besides the beauty that vaults these caverns, be wary if you are to visit as temperatures reach up to 112 degrees Fahrenheit or about 44 degrees Celsius with 90 to 100% humidity. Enough to leave you shimmering with sweat just like a crystal.