There are several other buildings that make up the cathedral complex in the Piazza dei Miracoli, each of which requires a ticket to enter. The Baptistery is particularly worth a visit, as it’s the largest baptistery in Italy, standing 180 feet (nearly 55m high). Baptisteries were once necessary as unbaptized people weren’t allowed inside the main building of the church, so baptismal fonts were either in separate buildings or found in the entrance to churches so that new members of the faith could be safely baptized before entering. The baptistery of Pisa is one of the few still in use for its original purpose but don’t worry, today you can visit the cathedral building without needing to be a baptized Christian. The Campo Santo (or Camposanto Monumentale) is a Gothic cloister allegedly built around sacred soil from Golgotha, brought to Pisa after the Third Crusade. Although it was not initially intended to be a cemetery, that’s what the space was eventually used for. Today visitors can explore the beautiful and calm arcades and chapels, see the Roman sarcophagi, and admire the restored frescoes. The Sinopie Museum is inside the Ospedale Nuovo di Santo Spirito and features sinopia, the drawings that artists use to prepare for painting frescoes. The artworks, which were mostly rescued from the Camposanto during World War II, date back to the 14th and 15th centuries and have been vital in helping art historians figure out which artists worked on which frescoes inside the Camposanto. The museum provides an interesting opportunity to learn more about the process of creating a fresco.