Dannevirke

Ancient line of defensive earthworks in Schleswig, north Germany, built by the Danes under Godfred during the reign of Charlemagne, in 808; it formed the border between Germany and Demark. It is to the north of the River Eider, and extends for 16 km/10 mi from the River Schlei to the River Treene. It was enlarged in the 12th century.

Later it fell into ruins, but was repaired in the 19th century and pulled down by the Prussians after their victory over Denmark in 1864. Its remains have yielded interesting archaeological finds.