At the beginning of the 20th Century Europe, including Russia, went through a lot of change. Uprisings occurred, some successful and some not. The world was hit by recession and the whole area was full of ever changing alliances.

In the early 1930s, both Nazi Germany, and the Soviet Union, were isolated from the international community. When Hitler annexed Austria and occupied Czechoslovakia, a lot of Western democracies raised concerns over Germany's strategy.  Meanwhile, Stalin's Soviet Union, had been though a lot of changes in the 20's and 30's. They were weary of the growing threat of Fascism in Europe and the Japanese focus on expansion. They wanted to secure their borders.

This opened the way to a very unlikely collaboration, and in August 1939 the Allies were suprised when Nazi Germany and the Soviet Union signed the Molotov-Ribbentrop Pact, a non-aggression treaty. The contract contained many conditions, including how Europe would be divided between the two regimes.  This gave Germany a free hand to wage war in Western Europe.

This strange and uneasy alliance, took the threat of Russia coming into the war out of the equation for the Nazi's, and opened the doors to Europe for Hitler.  The contract was supposed to mean that Russia's focus could be on Japan, not Europe.  The agreement seemed to be working. When Hitler invaded Poland, the country was divided and the Soviets occupied Eastern Poland as per the terms of their agreement. 

Operation Barbarossa was Adolf Hitler's plan to invade the Soviet Union. The motivation for this was twofold.  Firstly Hitler was a strong believer in the 'Stab in the back' conspiracy.  This was that Jews and Revolutionary Socialists (aka communism) had conspired to end the 1st World War with Germany's defeat. He believed they should have won. The second reason was a land grab for his Lebensraum and the expansion of Germany. It was the largest military invasion of the 2nd World War, with a three prong attack along a front stretching over 2,900 kilometers.

The Soviets were suprised by the attack and took time to organise, meaning that initially the Germans made significant gains.  They advanced deep into Soviet territory and encircling a number of Soviet forces. At one stage there were fears that Moscow itself might be invaded.

However, as the seasons changed, the Germans started to face conditions they were not used to.  There strategy had been one of suprise and the deeper into enemy territory that they went the harder it was to replenish supplies.  The Russians had organised a scorched earth policy meaning there were no supplies for the Germans to raid on the way.   When winter finally arrived, the army and their equipment struggled with the cold. Tanks got stuck in muddy terrain and it slowed down their assault.

Operation Barbarosa had a devastating effect on western areas of the country.    Places such as Stalingrad were sieged, and many died from starvation. The Soviet Union faced an immense human toll, with millions of soldiers and civilians killed, wounded, or taken prisoner.

The Soviets soon mobilised, and they were used to the climate and terraine,  The Red Army launched counteroffensives, steadily pushing the Germans back. The Battle of Stalingrad was the turning point in the war, and saw the Soviets achieve a decisive victory, halting the German advance and marking the beginning of the end for Nazi's in the East.

Operation Barbarossa's failure significantly impacted Germany's war effort. The costly diversion of resources to the Eastern Front weakened Germany's military capabilities elsewhere, and the prolonged conflict strained its economy and manpower.

Moreover, the Soviet Union's resilience and determination in the face of immense adversity earned it immense respect and admiration from the Allied powers. The Western Allies recognized the importance of the Eastern Front in the overall war effort and began providing vital military and logistical support to the Soviet Union.

'The enemy of my enemy is my friend.'   With the invasion of the Soviet Union, Stalin was quick to change sides.

Stalin and the Allies had a very different focus. Although the West wanted the Soviets support, they were also weary of the country's past pact with the Nazi's and it's ideology of Communism. The Soviets needed to split the Nazi resources and wanted the allies to open another front. The Allies were reluctant to stretch their own resources. But their common goal eventually led to them working together. Strategically the alliance made sense, the US had vast industrial and economic resources, and were able to provide military supplies. Whereas Britain and its Commonwealth had developed, tactical experience and had spies imbedded in Europe, the Soviet's had a large amount of people, who were used to the conditions they were fighting in and putting up strong resistence.

The Red Army was tenacious and pushed back the invading German forces. The strength of the Russians, coupled with the Allies opening up a second front was ultimately what defeated the Nazi's. While the Axis focussed on the Soviets, it gave time to the Allies to plan the Normandy landings on June 6, 1944, also known as D-Day. With the Allies invading from the West and the Soviets pushing back from the east, it was less than a year before both forces met in Germany to claim victory over the Nazi's on May 1945. The alliance had been successful, but now it was no longer needed.