Duomo, it is also called Cathedral of Sant Pietro Apostle, and it is the most important place of worship of the city. It extends on the east side of the square and includes the Baptistery of San Giovanni, the Duomo, the Bishop and the canonicals. The Duomo is a picturesque church with seven hemispherical domes. Inside there are three naves with mosaics on the floor and on the walls. The crypt is the only part remaining intact of the ancient cathedral (pheraps dating back to 1040), characterized by a lot of columns with carved capitals is a place of great beauty. In the crypt there are also the bishops' tombs of the city.