225° F (105° C) heat index. Easily impaled on 55-ton jagged crystals that are 36 feet long ... made out of drywall (kinda). "Most cameras with moving parts and tape mechanisms simply will not work."
The gypsum crystals in the Cave of Crystals at the Naica mine in Chihuahua, Mexico, are some of the largest and most spectacular in the world. [Last link is a .wmv]