Smoleñ Castle was built in the Gothic style in the mid-14th century probably by Otto of Pilczy to the site of earlier wooden watchtower. It was enlarged after 1350 and again in the mid-15th century. The first document dates from 1394.
The castle was destroyed by the Swedish army in 1655. It has been in ruins since them.
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.