The Castle of Monte Sant’Angelo, just above the medieval center, was started in the ninth century when the impressive 18 meter tall Giants’ Tower was constructed. Later the castle was used as a residence and the Treasure Hall and Norman Tower were added. In the 13th century it was restored by Frederick II to house his mistress Bianca Lancia, who is said to haunt the castle, and it was again restored in the 15th century.
A museum in the castle holds artifacts recovered during recent restoration. Events are sometimes held in the courtyard during summer.
From some of the rooms at Palace Hotel San Michele there are good views of the castle.