Viterbo is an ancient city in the Lazio region of central Italy, the capital of the province of Viterbo. Apart from agriculture, the main resources of Viterbo’s area are pottery, marble, and wood. Viterbo’s historic centre is one of the best preserved medieval towns of central Italy. Viterbo is unique in Italy for its concentration of ‘profferli’, external staircases that were a frequent feature of medieval houses. In the valley of the Arcione River just to the west of Viterbo are a number of clear water springs reputed for the healing qualities of their waters. One of the most famous are the thermal springs known as the Terme dei Papi (Bath of the Popes).