Neuhaus castle dates probably back to the 13th century. It may have been built on the site of earlier 12th century fortified house. The pentagonal tower was added in the 14th century and the castle was rebuilt during the 16th century. The traffic on the Danube has been able to deny with chain from the chain tower, located below the castle. Neuhaus was besieged at least in 1381, 1386 and 1389.
References:I visited, and vacationed at Neuhaus in 1960. I have oil paintings of the castle and a floral watercolor that was given to my parents from the baroness who owned it and lived there.
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.