Bronze model of the Trelleborg Viking ring castle. Several bronze models of the longhouses are seen. The Trelleborg ring castle consisted of sixteen longhouses, arranged in four groups of four, within a large circular wall. It also had a fortified bailey outside this wall that consisted of fifteen longhouses pointed towards the centre of the circle. This structure is unique in Viking architecture. It is thought that it was built around 980AD. Filmed in Trelleborg, Zealand, Denmark.