Kong Knaps Dige (King Knap’s dike) is an ancient rampart dating back to the Iron Age. Today, the dike is about 200 metres long, up to 6.5 metre wide and 1 metre high, but it was originally both higher and longer. The dike was probably a fortification by the nearby River Haller Å, which served as a boundary between different tribes. The story goes that the Battle of Grathe Heath took place here in the 1157, when Svend Grathe was killed by his rival to the throne, Valdemar the Great. The dike is reportedly named after Svend Grathe, who was also known as Svend Knap. Kong Knaps Dige is protected today.