The system contains 110 kilometers of explored tunnels, making it one of the largest karst complexes in the world.
Archaeologists have discovered unique species of cave-dwelling invertebrates that exist only within this specific system.
The site features the 'Sima de los Huesos' of Ojo Guareña, which has yielded significant prehistoric remains.
Human occupation dates back to the Middle Paleolithic, with evidence of use as a refuge through the medieval period.
The cave walls in the Ermita de San Bernabé contain mural paintings depicting the life of Saint Bernabé dating back to 1705.
The cave system functions as a major aquifer for the surrounding Merindades region.
It was declared a Natural Monument in 1996 to protect its geological and archaeological integrity.
The cave levels were formed by the erosion of Cretaceous limestone layers.
Researchers have identified over 180 different species of flora and fauna in the surrounding protected area.
Ojo Guareña is one of the largest karst cave systems in the world, featuring over 110 kilometers of mapped subterranean galleries spanning multiple levels. It is a designated Natural Monument and a site of significant archaeological and anthropological importance, containing evidence of human occupation from the Middle Paleolithic to the Middle Ages. The system consists of six superimposed levels carved by the Guareña and Trema rivers. The Cueva Palomera serves as the primary visitor access point for guided underground tours. Visitors can also explore the Ermita de San Bernabé, a sanctuary built directly into the cave mouth featuring 18th-century wall paintings. The site is located in the Merindades region of Burgos, northern Spain. It is geologically defined by its complex network of passages and halls decorated with diverse speleothems. It functions as a protected natural space governed by the Junta de Castilla y León.
The entrance of the Ermita de San Bernabé offers a striking contrast between the rock face and the historical architecture.
Book your guided tour well in advance online as group sizes are strictly limited for conservation.
Wear a light jacket as the temperature inside the cave remains constant and cool year-round.
Combine your cave tour with a visit to the nearby ethnography museum to contextualize the historical findings.
Do not attempt to enter non-guided areas of the cave system, as these are restricted for scientific and conservation reasons.
Closed on certain weekdays during the low season; check the official website as operations fluctuate based on visitor demand and research activity.
Do not touch cave formations as oils from skin damage speleothems; strictly follow the guide's path.
