Danevirke

The Danevirke or Danework is a system of Danish fortifications in Schleswig-Holstein, Germany. This historically important linear defensive earthwork across the neck of the Cimbrian peninsula was initiated by the Danes in the Nordic Iron Age about AD 650. It was later expanded multiple times during Denmark's Viking Age and High Middle Ages. The Danevirke was last used for military purposes in 1864 during the Second War of Schleswig.