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Ojo Guareña Natural Monument

Updated: Jan 27, 2023

To the north of the province of Burgos, on the southern slope of the Cantabrian Mountains, it is a complex of caves of international importance. Area of ​​the Natural Monument: 13,850 Ha. Area included ZIS: 51,100 Ha.

“The Ojo Guareña Karstic Complex is one of the largest Karstic complexes in Spain with its 110 km of underground galleries distributed on different levels"

The Ojo Guareña Natural Area was declared a Natural Monument on March 27, 1996 and is part of the Castilla y León Network of Natural Areas (R.E.N). It was declared an Asset of Cultural Interest in 1991, although since 1970 these caves already had protection as an Asset of Cultural Interest due to the importance of their archaeological sites..

On a package of Coniacian limestone and dolomites, which rest on an impermeable substrate of marl and clayey limestone, the Guareña and Trema rivers have entered the interior of this Cretaceous massif, originating the karstic complex.

The Ojo Guareña Karst has about 400 cavities, several of which are connected to each other, forming part of the Main Network of the Ojo Guareña Karst Complex. Currently, 14 main cavities (and many more secondary ones) are connected to this Main Network, whose topographed development exceeds 110 kilometers. The actual development will undoubtedly be much greater, but the flooded galleries, landslides, clogging by sediments or by concretions and narrowness prevent their connection. The main mouths connected are: Palomera, Ailments, Bones, Cornejo, Cuatro Pisos, San Bernabé, del Moro, Sumideros del Trema, La Mina, Sumidero del Guareña, Rizuelos, Torcona, Torquilla and Villallana. There are many other main or secondary cavities that do not connect, sometimes by a few meters, being in other cases linked by water currents (verified by coloration).

Ojo Guareña is one of the most extensive set of caves on the Peninsula, of great speleological interest, with prehistoric sanctuaries inside and 190 taxaanimals (115 terrestrial and 87 aquatic), of which there are 36 endemic and 34 that are new to science. that makes Ojo Guareña "a biodiversity hotspot" (hotspot).

The Edelweiss Group carried out the first speleological exploration in 1956. Since then, remains of all the cultures that have inhabited the Iberian Peninsula have been found. Ojo Guareña is one of the few places in the world where it is still possible to follow the evolution of religiosity from the Paleolithic to the present day of Western man. The Footprints Gallery stands out: a set of barefoot footprints left by a prehistoric human group.

Relevant information

Address: Ermita de San Bernabe, 09568, Burgos

Phone: 645490288


Town: Merindad de Sotoscueva

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