Wewelsburg castle is perched atop a wooded slope close to Paderborn's airport. The fortification Wifilisburg was used during the 9th and 10th centuries against the Hungarians. The next castle was demolished in 1123/24 by revolting peasants. From 1301 to 1589, the Prince-Bishops of Paderborn assigned the estate to miscellaneous liege lords.
The masonry of both predecessor buildings was integrated in the current triangular Renaissance castle. In its current form, the Wewelsburg was built from 1603 to 1609 as secondary residence for the Prince-Bishops of Paderborn. Wewelsburg was taken several times during the Thirty Years' War. In 1646 it was occupied and then razed by Swedish troops – namely by the army commanded by General Carl Gustav Wrangel. After 1650, the mostly destroyed castle was rebuilt by Prince-Bishop Theodor Adolf von der Recke and his successor Ferdinand von Fürstenberg. He carried out some architectural changes; the three towers of the castle got their Baroque style domes.
During the Seven Years' War (1756–1763), the basement rooms were probably used as a military prison. In the 18th and 19th centuries the castle fell progressively into ruin. In 1802, during German mediatisation the castle came into the possession of the Prussian state . On 11 January 1815, the North Tower was gutted by a fire that was started by a lightning strike; only the outer walls remained. From 1832 to 1934, a rectory existed in the eastern part of the south wing of the castle.
In 1924, the castle became the property of the district of Büren and was changed into a cultural center. By 1925, the castle had been renovated into a local museum, banquet hall, restaurant and youth hostel. During the Nazi regime Wewelsburg was used a school for SS organisation, focusing to pseudo-scientific research in the fields of Germanic pre- and early history, medieval history, folklore and genealogy.
Today Wewelsburg hosts a Historical Museum of the Prince Bishopric of Paderborn, Wewelsburg 1933-1945 Memorial Museum and temporary exhibitions.
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.