The Gothic Palazzo Papale (Papal Palace) was built in the 13th century for popes to use as a retreat from the city. At that time Rome was a notoriously unhealthful place, ridden with malaria and plague and rampaging factions of rival barons. In 1271 the palace was the scene of a novel type of rebellion. A conclave held here to elect Clement IV's successor had been trailing on for months. The people of Viterbo were exasperated by the delay, especially because custom decreed they were responsible for the cardinals' board and lodging for the duration of the conclave. So they tore the roof off the great hall where the cardinals were meeting, and put them on bread and water. Sure enough, a new pope -- Gregory X -- was soon elected. Inquire at the nearby Curia to see the Hall of the Conclave.