Operation Barbarossa

Introduction
Hitler began planning an attack on the Soviet Union in mid-1940 and signed the directive for Operation Barbarossa in December. Stalin, refusing to believe the worst, disregarded abundant messages from his intelligence services about an impending aggression. When Germany finally invaded, on June 22, 1941, it came as a tactical surprise and caught the Red Army, already weakened by Stalin's purges, at a terrible disadvantage.
Why did Hitler invade the USSR?
Hitler was arrogant. He had signed a Non-Aggression Pact with Stalin, which meant that Germany could invade Poland safely…