A portion of the Hindenburg Line, a huge mass of barbed wire. Advance East of Arras. October, 1918. (Official caption) The Hindenburg Line (an Allied term for the German Siegfriedstellung, or Siegfried Position) was a German defensive position of World War I, built during the winter of 1916–1917 on the Western Front, stretching 80 km southeast from Arras to Laffaux, near Soissons on the Aisne. The Hindenburg Line- the last and strongest of the German army's defence - consisted of three well-defended trench systems. The Hindenburg Line was attacked several times in 1917, notably at St. Quentin, Bullecourt, the Aisne and Cambrai and was broken in September 1918, On 2-3 September 1918 the Canadian Corps broke open its northern hinge (the Drocourt-Quéant switch, or Wotan-Stellung) and compelled those German units west of the line to withdraw to it. At the end of the month of September another Canadian assault forced a crossing of the Canal du Nord, near Cambrai. Again outflanked, the Germans abandoned the line and continued their retreat to the east during the Hundred Days Offensive.