The imposing ruins of this 13C fortress are set in a spectacular location, high above the cliffs to the north of the island. Excavations carried out in 2007 suggest that the castle may have been built under King Valdemar II ("Valdemar the Victorious"), who reigned from 1202 to 1241. Subject to numerous foreign attacks and fits of covetousness, it was completely sacked in 1522. The National Museum of Denmark is carrying out an extensive restoration campaign.