Aizkorri-Aratz

Aizkorri-Aratz Natural Park extends over 15,919 hectares between Gipuzkoa and Álava and takes in the massifs of Altzania, Aratz, Aizkorri, Urkilla, Elgea and Zaraia. The high point of the Basque Autonomous Community is here: Aitxuri, at 1,551 m, followed by Aizkorri at 1,528 m. The chain acts as the watershed between the Cantabrian and Mediterranean basins, and three of the main rivers of Gipuzkoa rise from its rocks: the Deba, the Urola and the Oria.

The relief is steep and mostly limestone, which has generated a highly developed karst: underground drainage has cut an extensive network of cavities, shafts and swallow holes beneath summits that at the surface alternate rocky crests with broad high-altitude pastures. The climate is montane, with cold winters and mild summers, and rainfall ranging from 1,100 mm on the valley floors to some 2,000 mm on the high ground. Beech and oak woods cover the slopes and give way, as height is gained, to mountain plant communities.

Among its wildlife are the peregrine falcon, the griffon vulture, the wildcat, the pine marten and the alpine newt; the Provincial Council of Gipuzkoa also runs a project to monitor the bearded vulture in Aizkorri-Aratz and Aralar in order to understand its use of the habitat better. Grazing by latxa sheep is still a living, landscape-shaping activity. The park also concentrates cultural landmarks of the first order: the San Adrián tunnel, a natural passage bored through the rock along which the royal road ran and today a variant of the Way of St James, with its small chapel; and the Sanctuary of Arantzazu, hanging over a ravine in Oñati, beside which stands one of the park's parketxe visitor centres. It was declared a Natural Park in 2006, the same year as Armañón.