The retirement to the Hindenburg Line (/Operation Alberich/Alberich Manoeuvre) took place from February to March 1917. News of the demolitions and the deplorable condition of French civilians left by the Germans were serious blows to German prestige in neutral countries. Labour was transferred south in February 1917 to work on the from La Fère to Rethel and on the forward positions on the Aisne front, which the Germans knew were due to be attacked by the French. Divisions released by the retirement and other reinforcements increased the number of divisions on the Aisne front to early April. The Hindenburg Line was attacked several times in 1917, notably at St Quentin, Bullecourt, the Aisne and Cambrai and was broken in September 1918 during the Hundred Days Offensive.