The Hundred Days Offensive was a series of massive Allied offensives which ended the First World War. Beginning with the Battle of Amiens on the Western Front, the Allies pushed the Central Powers back, undoing their gains from the German spring offensive. The Germans retreated to the Hindenburg Line, but the Allies broke through the line with a series of victories, starting with the Battle of St Quentin Canal on 29 September. The offensive, together with a revolution breaking out in Germany, led to the Armistice of 11 November 1918 which ended the war with an Allied victory. The term "Hundred Days Offensive" does not refer to a battle or strategy, but rather the rapid series of Allied victories against which the German Army had no reply.