Cave of Crystals

A geologist explores the caves of giant crystals inside the Naica Mine in Chihuahua, Mexico. Scientists are petitioning the Mexican government to claim for Unesco World Heritage status to protect the unique formations for future generations.

Cave of Crystals



A rare glimpse of the cave of crystals.
Mexico’s Cave of Crystals stunned geologists when it was first discovered in 2000. The underground chamber contains some of the largest natural crystals ever found – some of the selenite structures have grown to more than 10m long. Professor Iain Stewart got a rare glimpse of the subterranean spectacle while filming for the new BBC series How the Earth Made Us.
Professor Stewart describes the cave as a geological wonder of the world

We kept on being told how difficult it was going to be to film in the Naica Cave, but nothing really prepares you for the extremes of that cavern.

It’s about 50C in there, but it’s the virtually 100% humidity added on top that makes it a potential killer.

That combination means that when you breathe air into your body, the surface of your lungs is actually the coolest surface the air encounters. That means the fluid starts to condense inside your lungs – and that’s really not good news.



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.

But when the first people went in to explore, they were almost overcome by the conditions – and there’s some pretty hairy video footage of them coming out of the cave on the verge of losing consciousness. So we knew the dangers were real.

Cave of Crystals