The place is a Mexican mine at Naica that some have dubbed the Crystal Cave of Giants. You can clearly see why. The crystals are made of gypsum, found when miners pumped put water to get to nearby silver deposits, and the entire cavern is adjacent to a magma chamber that makes the temperature a sweltering 120 degrees with 90% humidity. Hence the environmental suits with cooling packs that are necessary for survival.
An underground cave with giant crystals, nearby lava and a deadly permeating wet heat? I’m fairly certain some supervillain needs to make this his lair stat, baby. All it needs is a few strategically placed lasers.
Pics and story are from Discovery News.