Was built at the behest of Paternò-Castello family, Princes of Biscari, since the end of the seventeenth century over the walls erected by Emperor Charles V, designed by architect Alonzo Di Benedetto. The decoration of the seven windows overlooking the marina is work by sculptor Antonino Amato. Later, the building was modified and designed by Girolamo Palazzotto and Francesco Battaglia, to be completed until 1763. It is accessed by a large portal that leads into the central courtyard, decorated with a large-scale in shape of pincer. Inside, there follow the Rococo "Ballroom" with a complex decoration of mirrors, stucco and frescoes by matteo desiderato and Sebastiano Lo Monaco. The central dome, used as housing orchestra, is covered by a fresco depicting the glory of the family. You enter the dome through an ornate staircase in stucco, in the large Gallery overlooking the marina. Among other rooms, the "Feudi", the "Apartment of the Princess", the "Gallery of the Birds" and the "Room of Don Quixote". Of particular importance is the Museum, which was once the largest archaeological collection of Ignatius V. Among the distinguished visitors remembers Johann Wolfgang Goethe (1787). In 2008 the building was the backdrop to the video for the song "Violet Hill" of the British band Coldplay.