Germany and USSR signed a pact of non-aggresion before the invasion of Poland in 1939,but,their alliance would be short-lived.In the summer of 1941,Hitler launched Operation Barbarossa,ordering four million German soldiers to invade the Soviet Union across a front spanning three thousand kilometers.

Nearly a year before Wehrmacht reahed Stalingrad,the Red Army struggled to answer the threat of Operation Barbarossa.Towns and villages throughout the western USSR were evacuated as military forces dug in and prepared for the German assault.

After their desperate play to slow the German advance,Churkin and Isakovich fell back to Mtsensk -- a fortified village barely sixty kilometers from Moscow.The Wehrmacht would come in great numbers,with powerfull Panzer tanks,and the Soviets could not rely on scorched earth so close to the capital.

The Russian winter of 1941 transformed every battlefiled on the Eastern Front.While they struggled with frozen roads and blinding snowstorms,the Soviets adapted far better than their enemy.

The symbolic city of Stalingrad remained a key battlefield for more than five months,starting in the autum of 1942.It was characterized by vicious close-quarters combat,infantry attrition,Luftwaffe bombing,and the perilous Volga river crossing.

In a public address,Hitler vowed that the German army would never abandon Stalingrad.However,dwindling supplies and the approaching winter placed a heavy burden on the German forces in the city.With intelligence on the Wehrmacht's weakening support,the Red Army might have cleared the city by breaking German supply lines.

As Victory at Stalingrad drew closer for the Red Army,the northen city of Leningrad (now Saint Petersburg) was withering under a German supply blockade.For over a year the Wehrmacht pillaged and destroyed shipments of food and military equipment.

In the wake of Operation Spark,the city of Leningrad was safe from German capture and better supplied than it had been in more than one year.The new supply line was a godsend for the starving civilian populace,and soldiers on the Leningrad Front benefitted as well.

In the summer of 1943,the Soviets claimed victory in the battle of Kursk,the largest tank conflict in history.By the early autum,German Army Group Center was in full retreat,and the siege of Leningrad would soon be over.

Hitler and Stalin had invaded Poland as allies in 1939,but five years later,their armies clashed on many of the same battlefields.By July 1944,the Red Army had retaken the Ukraine and Belarus,and their next offensive aimed to push the Wehrmacht out of eastern Poland.

The Third Reich stole away Poland's autonomy,classified its people as sub-human and sent thousands to die in camps.The Polish armed forces numbered in the hundreds of thousands, and thousands more fought as militia but many Poles depised Germany and the USSR in equal measure.

The Red Army did not capture Warsow until January 1945,more than three months after the Wehrmacht crushed the Polish Home Army's desperate uprising.With his forces abandoning the Polish Capital,Hitler established a Festung (fortress) in the western city of Poznan.

Soviet forces had secured territory in Austria and Germany by the spring of 1945.They would soon begin a devastating artillery barrage on Berlin and mount their final assault on the Third Reich.As the Soviets approached the German capital,they showed no mercy to the remaining Wehrmacht defenders.

Stalin demanded the capture of Berlin.He rightly predicted a conflict with the western allies over who would control Germany after the war,and as such he urged Soviet commanders to claim victory before United States.