What is the Danevirke? Over 1000 years ago in the Viking Age, Danes, Frisians, Saxons and Slavs came into contact in this border region between Scandinavia and Central Europe. Danish kings began to fortify the Danevirke to secure the southern frontier of their kingdom and protect the trade route between the North Sea and the Baltic. The Danevirke consisted of earthworks, walls, ditches and an offshore defensive structure in the Schlei. The most important trading centre and transport hub was Hedeby.
Large areas of the Danevirke and the whole area of Hedeby are protected by a nature reserve. The species, which occur in this area are rare and form parts of a previously biodiverse landscape. Mat-grass, acid grassland, dwarf-shrub heath and different forms of oak coppice used to be wide-spread. These habitats developed from historical land-use techniques, which do not exist today. The aims of nature protection and monument conservation are closely related in the Danvirke and Hedeby areas