Visitors to southern Spain can now step inside an otherworldly rock formation: a giant geode. The attraction near the town of Pulpí recently opened to the public. It’s one of the largest crystal-filled rocks ever discovered.
The geode began forming millions of years ago as mineral-rich water seeped underground. The water slowly evaporated, leaving behind crystallized minerals. Some of the crystals grew to be 7 feet long!
To enter the geode, people squeeze through a small opening at one end. “The first time I stepped inside, my heart raced because I was seeing something incredible,” says Javier García Guinea, a geologist at the National Museum of Natural Sciences in Madrid, Spain.