First built by the Byzantines, Amantea Castle was strengthened by the Arabs. The current cylindrical tower is however to the Norman-Hohenstaufen age. It was long besieged by Charles of Anjou's troops in 1269. It was nearly destroyed in the earthquakes of 1638 and 1783 and during the French siege in 1806-1807. It is now a public structure, but is abandoned.
Castle, now in ruins, is on plateaux with a beautiful view both on small bay of Oliva river, on Tyrrhenian sea, and Catocastro river valley.
Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.