Nassenfels castle dates from the 12th-13th century. The first reference to the castle is dated to 1245, when Count Gebhard III of Hirschberg was assassinated when he was besieging Nassenfels castle. The castle was reconstructed and enlarged later and the current appearance dates from c. 1400. The three towers were built by bishop Friedrich von Oettingen. Nassenfels was again restored in 1464 and 1699. in 1807 the castle was sold to private owners and used as a quarry.
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.