The Day When... S01 E04 The Day When Hitler Lost The War

Hitler's downfall began on 22nd June 1941, when he launched the largest military offensive in history against the Soviet Union - Operation Barbarossa. By opening this eastern front, the Führer, blinded by power, signed his own death sentence. So why did Hitler open a second front after always saying he wouldn't? Why did he suddenly attack the Soviet Union and why did Stalin foresee the attack?