Troldborg Ring is situated north of the Ravning bridge. This ring castle lies 70 ms above the river valley on a hill projection with a very steep drop down towards the meadow. The castle is surrounded by a rampart and on the landward side, there is also a moat.
No other Danish prehistoric castle has had a similarly dramatic location. Before the castle was built, the area was unfortunately exposed to a lot of burning. No one knows what the reason for the huge fire might have been. The castle was built 100-200 A.D. and was in use up to around the third century A.D.