The Santuario de Arantzazu, of modern design and of great architectural interest in its attempt to integrate into the site's abrupt natural landscape, was built by architects Francisco Saiz de Oiza and Luis Laorga between the years 1950 and 1955. For the decoration of the altarpiece, the painter sculptor of Madrid, Lucio Muñoz was chosen, and Eduardo Chillida was commissioned for the works on the access to the basilica. The Sanctuary has a Latin Cross layout, and was built over an old church which still remains on a lower level as a crypt. The apse is semi-circular and the most outstanding feature of the portico is the decoration at the front with a frieze of anthropomorphic figures sculpted on large limestone blocks by sculptor Jorge Oteiza. The entire crypt is covered in large individualised murals and the storeys are the work of Nestor Basterretxea. The image representing the Andra Mari of Arantzazu, after which the temple is named, is to be found in the central niche of the altarpiece. It is a gothic image whose origin is situated between the 13th and 14th centuries.
