Ever since World War I, Germany was not on a friendly terms with Russia. Germany hated the Soviet Union and despised communists. This very hate for communism was what allowed Hitler to promote his Enabling Act providing unlimited power and creating a totalitarian state. Germany had previously suffered from various terrorist attacks and the infamous alleged communist attack on the Reichstag building. While the true motivations and attackers remain debatable, this attack on the Reichstag building caused Germany (and Hitler) to take action against the communist.
Hitler's main war aim was to create "lebensraum" or in other words living space for the expansion of Germany. The need for "lebensraum" was described by him in his book "Mein Kampf" (My Struggle)published in the 1920's. Hitler believed that the place for this expansion was to the East of Germany. For this reason he invaded Poland in 1939. The attack on Poland was a clear sign of aggression, Britain and France could no longer ignore Germany and declared war against Germany. Germany with it's new tactic Blitzkrieg outmatched that of France and Britain's. Soon France was defeated and Britain was forced back to the other side of the English Channel. Much of Western Europe was now under control of Nazi Germany and it was time to take the West.
Germany had a Non-Aggression Pact with the Soviet Union. This gave Stalin a sense of security. Hitler knowing that the peace between Russia and Germany would be difficult to maintain. Soon,Hitler launched operation Barbarossa for the following reasons.
*Hitler have always hated the Soviet Russia because of their communist ideology.
*Hitler believed the Russian population were inferior and therefore should be exterminated.
*Hitler, being a nationalist he is, wanted more land for Germany
*There were strategic objectives in Russia which Hitler deems as necessary to win the war.
(Ukraine to the south of Russia was needed to feed German soldiers, Caucasus was a vital oil supplies and this was needed to have a functioning mechanized army.)
Operation Barbarossa was a wild success initially. The Red Army was ill-prepared for the German surprise attack. At the time, Germany had one of the most experienced army in the world and it was the only nation in the world that utilized Blitzkrieg tactic. The Red Army was quickly wiped out by the Wehrmacht. Soon, German had gained control of much of Western Russia. As time goes on though, Germany started to lose for the following reasons.
Firstly, Hitler underestimated the potential of Red Army. The size of Red Army was twice the size of what was to be expected. Armies that were destroyed or defeated during the early phase of Operation Barbarossa were soon...