Valangin castle was a residence of the local lords from mid-12th century to 1566. The oldest visible remains date from the 13th century. It consists of a courtyard surrounded by a rampart and a 'donjon' (keep), which hosts the current museum.
Since 1430 the castle was altered with semicircular towers to be defended against the firearms. The castle was damaged by fire in 1747 which destroyed a whole wing. The dungeon was restored and partly rebuilt between 1769 and 1772. Today Valangin castle is a museum.
References: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.