A massive, and initially very successful, German attack on the Allied lines. It was launched by General Ludendorff on 21st March 1918 against Sir Hubert Gough's depleted Fifth Army on the old Somme battlefield. The Germans broke through the British lines and moved into open countryside behind the British trenches. For a time the British and French position was critical, but the Germans did not have the reserves to carry through their advances, and Allied resistance was stiffening as more American reinforcements began to arrive. The offensive was finally reversed in a major Allied counter-attack in August 1918.