 D-Day and the liberation of France as a strategy were instrumental to the success of Operation Bagration, the Russian counter-offensive, which forced Hitler to open up new fronts.By the end of February 1944 Army Group North had been defeated and the German siege of Leningrad was lifted, a sign of the commencement of the Russian counter offensive.Operation Bagration, pioneered by General Zhukov was launched in June of 1944 and employed 1 million men and 2 thousand aircraft to encircle and destroy the German Army Group Centre, which pushed the Germans into retreat and liberated eastern Europe.