A thousand feet (304 meter) underground, the Cave of Crystals (pictures) is just one of a series of glittering caverns beneath the Desert in the Mexican state of Chihuahua near Naica (map). Much of the complex would naturally be filled with scorching water, were it not for industrial pumps that facilitate the mining of silver, zinc, lead, and other minerals in the caves.
The temperature in the cave is about 50C, and it’s the virtually 100% humidity. When the cave was first discovered it was just an accident. Miners working in the Naica silver mine broke through the walls of the cavern and were astounded to discover these enormous crystals – the biggest anywhere on Earth.