Hitler's campaign against the Soviet Union started by sending 7.2 million troops into the Soviet land. They caught the red army off guard and had a quick success. By July 17th, the Germans were less then two miles from Moscow. The attack was postponed as the winter immobilized tanks and made it difficult for troops to move. The Red Army was quite ready and used the snow to begin a counterattack against the Germans. This forced the Germans to retreat. Hitler was not yet finished however.