The Aizkorri-Aratz Natural Park, located between the provinces of Álava and Gipuzkoa and stands out for its Limestone Mountains and endless beech forests. It has the highest peak in the País Vasco, Aitxuri (1,551 m). Legend has it that the mythological goddess Mari can still be found among its peaks. 

The main entrance to the park is located next to the spectacular Sanctuary of Arantzazu, hanging on a pronounced ravine; it is a must-see for its architectural and artistic interest. In addition, the Álava town of Araia also serves as access and starting point to ascend to Aratz (1,443 meters).

The Aizkorri Aratz park houses other treasures such as; the San Adrián Tunnel, which hides inside a hermitage of the same name and a medieval road that was very busy in another era or the underground cave of Arrikrutz in Oñati, with galleries adorned with gigantic stalactites.