Fyrkat — Wikipedia

Fyrkat is a former Viking ring castle in Denmark, dating from c. 980 AD. It is located near the town of Hobro, some distance from the present end of the Mariager Fjord in Northern Jutland. The fortress is built on a narrow piece of land, with a stream on one side and a swampy area on the other side. Likely built during the reign of Harald Gormsson or his son Sweyn Forkbeard, the fortress may have served as barracks or as a defensive stronghold. It would have helped to enable control of the traffic on the main land-based trading route between Aalborg and Aarhus. Because of its unique...