Viterbo's 15th-century city hall overlooks Piazza del Plebiscito, the elegant Renaissance square that has long been the city's political and social hub. It's not all open to the public, but you can visit a series of impressively decorated halls on the 1st floor whose 16th-century frescoes colourfully depict Viterbo's ancient origins. During the week, the entrance is at Via Ascenzi 1; at weekends it's on Piazza del Plebiscito.
Outside, the elegant courtyard and fountain were added two centuries after the palazzo was completed in the late 1400s.