Germany's invasion of the Soviet Union in 1941 was the largest troop offensive in military history. And the Battle of Stalingrad is arguably the deadliest single battle the world has ever seen. The eventual Russian victory has long been lauded as a shining example of Stalin's military genius. He is said to have baited the much more powerful and technologically advanced German army with a carefully executed withdrawal, then caught the Nazis unprepared in vicious city-block-by-city-block fighting that decimated the German forces. By the time the battle was over, more than one million lives had been lost and the course of the war permanently altered. But 70 years after the battle was fought, newly uncovered documents, survivor accounts and stunning archival footage are revealing a different picture.