image creditDig in deep into the Naica Crystal Caves in Chihuahua, Mexico, and get nothing less than massive crystals. The cave conditions are extreme: it has a constant temperature of 58 degrees Celcius (136 °F) and very high humidity.
Trekkers are given a suit full of icebags with a respirator when they had to explore the cave. And they got to move quickly because the longer your stay in there, the more you lose your brain functions.
