Aggersborg is the remains of Denmark's largest ring castle from the year 980. The area was protected in 1990 and the embankment itself was re-established so that you can clearly see the extent of the rampart and its extent. There is a path around the area. Access to an exhibition about the castle and the toilet during the summer months (Easter to the autumn holidays).
Aggersborg was added to UNESCO's list of World Heritage Sites on 17 September.
See more about Aggersborg at Vesthimmerlands Museum's website.