The Church of Nuestra Señora de Estíbaliz, which dates from the 12th Century, is a Romanesque temple found in the Álava town of Argandeña, providing one of the best examples of Álava Romanesque. The church is set out as a Latin cross with a triabsidial head, with a transept of the same width and a single nave.
On the exterior, worthy of note is the southern facade known as Porta Speciosa, formed by four slightly pointed archivolts with sculpted jambs with figures of entwined flowers and other phytomorphic motifs. Moreover, in the inside we find different spaces covered with cul-de-four vaults, of half-barrel vaults and ogees in the transept with interesting figured capitals