Armañón

Armañón Natural Park is the westernmost in Bizkaia and occupies the far end of the Las Encartaciones district, between Karrantza and Turtzioz, on the boundary with Cantabria. It was declared in 2006 and its relief combines two very different registers: the gentle sandstone forms of Mount Armañón, which reaches 854 m, and the steep limestone massifs of Peñas de Ranero (737 m) and Los Jorrios (837 m). On the limestone a very complete karst has developed, with limestone pavements, dolines and fissures at the surface and more than 200 caves and shafts catalogued underground.

That underground world is the park's great asset. The Pozalagua cave, discovered in 1957 during quarrying, is a single chamber some 125 m long by 70 wide and 12 high that holds the largest known concentration of helictites in the world: millimetre-scale formations that grow in all directions in defiance of gravity and intertwine above all in what is called the Versailles chamber. Nearby opens the Torca del Carlista, one of the largest underground chambers in Europe. The cavities are also of high biological value: the park hosts the main breeding colony of the Mediterranean horseshoe bat, a threatened species, among several bat species.

At the surface the mosaic alternates oak, beech and mixed broadleaf woods with pastures and farmed countryside. The botanical jewel is the Sopeña holm oak wood: a Cantabrian holm oak stand that survives thanks to the microclimate created by the rock wall, which shelters it from the cold winds and reflects the heat, and that offers a Mediterranean scene in the middle of the Cantabrian coast. Eagles and vultures breed on the crags. The rural character of the setting shows in the native breeds still kept here — the blonde-faced and black-faced Carranzana sheep, the Monchina cow, the Villano de Las Encartaciones dog — and in a heritage that includes dolmens and barrows with a signposted megalithic route. The park's interpretation centre, next to Pozalagua, occupies the buildings of the former dolomite works.