The Roccella Ionica Castle sits on a rocky promontory at 104 meters, overlooking the village. Founded during the Norman period by Gualtieri De Collepietro, it later passed to the Ruffo family, then to Galeotto Baldaxi, and finally to the Carafa della Spina family, who restored it between 1479 and 1806. The fortress withstood attacks, including from Turkish corsair Dragut Pasha in 1553. The palace features ruins, including a stone portal with the Carafa crest, a monumental balcony with carved figures, and a courtyard with a star-shaped drainage system. Next to the castle is the Baroque-style Mother Church of St. Nicholas, once connected to the palace by a private choir. The church houses valuable polychrome marble altars, now national monuments.
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.