The city's bullring, opened in 1880 and named after a local matador, hosts bullfights during the August festival and is otherwise used for concerts and large events. The capacity is around 9,000.
Bullfighting is in steady decline in the Basque Country (it has been banned outright in some other parts of Spain) and the August feria draws progressively smaller crowds. The brick-and-stone facade is worth a look even when the venue is closed.