In the north of the province of Palencia lies a territory of rugged mountains, pleasant valleys and little human intervention, which has favored the conservation of exceptional environmental conditions.

In terms of landscape, the Natural Park is of overwhelming beauty due to the variety of species that cover it, especially highlighting the Tejeda de Tosande, one of the oldest yew forests in Europe with specimens that are close to a thousand years old.

If the flora is rich, the fauna is no less so, which here concentrates a good number of Cantabrian endemisms such as the chamois or the piornal hare, although the most important representative is the brown bear that shares the territory with the Iberian wolf and the cat. mountain, among others.