Gothic-style 14th-century cathedral, named after Bilbao's official patron saint. Three naves and small Gothic cloisters. The building was designated a cathedral in 1949. Its Neo-gothic tower and main façade were designed by Severino de Achúcarro in the 1800s. The adjoining square (Plaza de Santiago) bosts a fountain designed by Luis Paret during the reign of Carlos III with the inscription Por el bien público (For the good of the people).