World War One was largely fought and won on land but this could not have taken place without the movement of ships. Command of the sea enabled the Allies to bring in the vital resources and manpower required to prevail on the Western Front and elsewhere. At times, the Germans inflicted damage on the British fleet, notably at the Battle of Jutland in 1916, the largest clash of big-gun battleships of all time. Yet the Germans were never near gaining command of the sea. Their U-boats, by their successful attacks on merchant ships, did come close to denying command of the sea to the Allies, especially in 1917, but, by bringing the United States into the war, this campaign only sealed Germany's fate.