This isn't a movie set, those are actual people exploring fascinating Naica crystal caves in Mexico. These selenite crystals formed under water as oxygen diffused down and reacted with minerals in the water. A mish-mash of interdisciplinary projects are underway involving geochemists, astrophysists, photographers and many others. They've invented special ice suits to survive the sweltering environment, documented crystal formations found no where else on earth, and are working to conserve unique cave environments throughout the region. 