The Medieval Elephant Tower is the second highest of Cagliari, one of the most important monuments of the city, after the St. Pancrazio Tower. It served as a defense for numerous Moorish and Genoese attacks, as well as the main entrance to the Castle. It was built in 1307, on the orders of the Pisa Consuls Giovanni De Vecchi and Giovanni Cinquini. In 1328 it was closed on the north side to create homes and warehouses. In the Spanish era, the building was used as a prison and its doors were hung the severed heads of prisoners sentenced to death and beheaded in the nearby "plazuela" (now Carlo Alberto Square). In 1906 the Tower was restored by Dionigi Scano, who brought it back to its original state: the three outer sides are in white limestone from Bonaria, the fourth, is open to the typical way of Pisa and shows the four-story buildings built on wooden mezzanines. The door was defended by numerous weirs and two gate valves, while for the defense from above, a series of shelves were holding a wooden scaffold.