Operation Barbossa: the German Invasion of the Soviet Union
Before the battle: After conquering most of Eastern Europe Hitler went back on his non-aggression pact with the USSR and launched Operation Barbarossa. He launched an overwhelming number of troops and conquered lots of Soviet land counting on surrender in the face of this quick and impressive display of power. However the Soviets were resilient and Hitler was soon forced to scale back his forces because of problems supplying the troops. The invasion began to stall as winter set in. Then in the spring of 1942 the Germans restarted their invasion on the southern part of the front.

The Battle of Stalingrad was fought from July 17, 1942 to February 2, 1943. The battle was one of the bloodiest battles in history there were over a million Soviet casualties and over 800,000 Axis casualties. Hitler wanted to seize the city to gain an important point on the Volga river so he could cut off supplies. The siege became a large waste of troops and supplies for the German army. The Soviet winter became a huge problem for the Germans who were not equipped for the grueling winter.
Troops storming one of the factories in Stalingrad
Troops storming one of the factories in Stalingrad
Although the Germans at one point had control of all but about 10% of the city the Soviets refused to yeild and forced German action. Multiple attempts to encircle the Soviets failed and they were then able to break out and enact their own offensive. The battle was a turning point that led to a steady march of Soviet troops going back towards the German borders.

Because of the importance given to the taking of the USSR during this time the Germans were forced to ease up on the Western Front and gave British and American troops time to group and enact Operation Torch and the African Campaign.