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.
Varberg Fortress was built in 1287-1300 by count Jacob Nielsen as protection against his Danish king, who had declared him an outlaw after the murder of King Eric V of Denmark. Jacob had close connections with king Eric II of Norway and as a result got substantial Norwegian assistance with the construction. The fortress, as well as half the county, became Norwegian in 1305.
King Eric's grand daughter, Ingeborg Håkansdotter, inherited the area from her father, King Haakon V of Norway. She and her husband, Eric, Duke of Södermanland, established a semi-independent state out of their Norwegian, Swedish and Danish counties until the death of Erik. They spent considerable time at the fortress. Their son, King Magnus IV of Sweden (Magnus VII of Norway), spent much time at the fortress as well.
The fortress was augmented during the late 16th and early 17th century on order by King Christian IV of Denmark. However, after the Treaty of Brömsebro in 1645 the fortress became Swedish. It was used as a military installation until 1830 and as a prison from the end of the 17th Century until 1931.
It is currently used as a museum and bed and breakfast as well as private accommodation. The moat of the fortress is said to be inhabited by a small lake monster. In August 2006, a couple of witnesses claimed to have seen the monster emerge from the dark water and devour a duck. The creature is described as brown, hairless and with a 40 cm long tail.