Add Yahoo as a preferred source to see more of our stories on Google. The interior of the Cave of Crystals in Mexico with a person for scale. The Cave of Crystals is an underground cavern filled with ...

Miners drilling through limestone in Chihuahua, Mexico, broke into an extraordinary chamber in 2000 and found something that defied geological expectations: gypsum crystals taller than telephone poles ...

Three hundred meters beneath the surface of Chihuahua, Mexico, a limestone chamber holds some of the largest natural crystals ever documented, some stretching well beyond the height of an average ...

These huge gypsum crystals in Mexico's Naica caves, some up to 12m long, have been growing for tens of thousands of years -- but scientists have only now discovered what's inside them. "We've ...