St. Pancrazio Tower is the highest Pisan tower of Cagliari. The building, a symbol of the city, is located at the highest point of the Castle District. It was built in 1305 by architect Giovanni Capula. Later it was closed on the side of the Castle to create homes and warehouses. In the Aragonese period the building was used as a prison. As the twin Tower of the Elephant, it is made of white limestone from Bonaria. On the three closed sides, the thickness of three meters, presents various slits; the fourth side shows the galleries located on the four floors of the tower. The area in front, known as "St. Pancrazio Area", became in 1823 Hospital of Prisons, and at the beginning of '900 was used as storage of archaeological materials.