Operation Michael was a major German military offensive during the First World War that began the German Spring Offensive on 21 March 1918. It was launched from the Hindenburg Line, in the vicinity of Saint-Quentin, France. Its goal was to break through the Allied (Entente) lines and advance in a north-westerly direction to seize the Channel Ports, which supplied the British Expeditionary Force (BEF), and to drive the BEF into the sea. Two days later General Erich Ludendorff, the chief of the German General Staff, adjusted his plan and pushed for an offensive due west, along the whole of the British front north of the River Somme. This was designed to first separate the French and British Armies before continuing with the original concept of pushing the BEF into the sea. The offensive ended at Villers-Bretonneux, to the east of the Allied communications centre at Amiens, where the Allies managed to halt the German advance; the German Army had suffered many casualties and was unable to maintain supplies to the advancing troops.

The Hundred Days Offensive was a series of massive Allied offensives that ended the First World War. Beginning with the Battle of Amiens on the Western Front, the Allies pushed the Imperial German Army back, undoing its gains from the German spring offensive.