In 1999, the largest geode in the world was discovered inside an abandoned silver mine in Spain’s Almeria Province. Closed in 1969, this cave is now rich for geologists because it contains the Pulpi Geode, a giant rock cavity filled with shimmering crystals. While not everything is known about how geodes are formed, these structures contain a wide variety of minerals.

The Pulpi Geode is 8 meters wide, 2 meters long, and 2 meters deep, making it the largest on earth. Since opening to the public in 2019, more than 100,000 visitors have come to Pulpi to marvel at the wonders of nature and the silver mine’s history.

The Pulpi Geode continues to offer new discoveries as scientists search for when and how this richest of rocks came to be.