Official Portal of Tourism. Junta de Castilla y Leon

More than four kilometres in length, and of great geological beauty, this is the world’s sixth longest cave of its kind. It is situated in the town of Puras de Villafranca, in an area of conglomerate rocks cemented with limestone motifs from the Oligocene, deposited 35 million years ago.

The river flows through the lower section of this stunning cave, which boasts a vast number of eccentric formations, tours, flowing forms, stalagmites, stalactites and columns, formed by lithogenesis on the floors, walls and ceilings, making this one of the most important caves of its kind in the world. The cave’s three levels are guaranteed to surprise visitors, and the most spectacular and unusual phenomena are to be found on the top two levels. The sheer grandeur and geological uniqueness of this cave are undoubtedly its most outstanding features.