Historic defensive lines

line of fortifications along the French/German border

German defensive line used in World War II

The Danevirke or Danework (modern Danish spelling: Dannevirke; in Old Norse: Danavirki, in German: Danewerk, literally meaning earthwork of the Danes) 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.

fortified line of World War I

chain of fortifications built by Israel

system of border fortifications built by the Soviet Union

propaganda

fortified line of defense built in the Pyrenees between 1944 and 1948 to prevent an invasion of the Spanish territory.

World War II defensive line in south west England