It's "the Sistine Chapel of crystals," says Juan Manuel García- Ruiz.
The geologist announced this week that he and a team of researchers have unlocked the mystery of just how the minerals in Mexico's Cueva de los Cristales (Cave of Crystals) achieved their monumental forms.
Buried a thousand feet (300 meters) below Naica mountain in the Chihuahuan Desert, the cave was discovered by two miners excavating a new tunnel for the Industrias Peñoles company in 2000.
The cave contains some of the largest natural crystals ever found: translucent gypsum beams measuring up to 36 feet (11 meters) long and weighing up to 55 tons.
"It's a natural marvel," said García-Ruiz, of the University of Granada in Spain.