A 16th-century palace on the corner of Plaza del Machete and Calle Fray Zacarías Martínez, built into the medieval city wall. The building incorporates a stretch of the old town's defences in its lower walls — visit the basement to see the masonry.
It is now a venue for civic events, weddings, and a regular programme of pintxo-pote competitions. Worth a look from outside even when nothing is on. The terrace at the back, looking out over the lower city, is one of the better viewpoints in town.