Caption: "Prisoners in a clearing depot in Abbeville after the Battle of the St. Quentin Canal, 1918." The Battle of St. Quentin Canal was a pivotal battle of WWI that began on September 29, 1918 and involved British, Australian and American forces in the spearhead attack and as a single combined force against the German Siegfried Stellung of the Hindenburg Line. Under the command of Australian general Sir John Monash, the assault achieved all its objectives, resulting in the first full breach of the Hindenburg Line, in the face of heavy German resistance and, in concert with other attacks of the Great Offensive along the length of the line convinced the German high command that the writing was on the wall regarding any hope of German victory.