You cannot visit the Cave of the Crystals. Not with a permit, not with money, not even as a scientist: the chamber has sat flooded and sealed since 2015, and nobody has been inside since. That single fact makes most “how to visit” content about it wrong before it gets to paragraph two. What is real is the geology: a chamber roughly 300 meters down in Mexico’s Naica mine, holding selenite crystals up to 11-12 meters long and an estimated 12 tonnes each, among the largest ever documented on Earth, grown over as long as a million years in mineral-rich water a magma body kept near 58C.

“Worth the trip” splits into two honest answers here. The trip to the cave itself: no, because there isn’t one to take. The Cave of the Crystals sits roughly 300m down inside the Naica mine in Chihuahua state, and the mine flooded and sealed the chamber back in October 2015. Nobody has been inside since, not tourists, not scientists. Air in there still runs up to around 58C, hot enough to kill an unprotected person in about ten minutes.