In the center of the village Íllora, at the top of a rock, there are the ruins of the old castle, although there are hardly any remains of the walls. This castle dates from the Caliphate period (9th-10th centuries) and is structured in three areas: the villa, the citadel and the suburb. Associated to that castle, there are a series of optical towers, among which the Tower of Brácana stands out.
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.