Nazi Germany's assault on the Soviet Union in the summer of 1941, Operation Barbarossa, was the largest invasion in history. Almost 3.5 million men smashed into Stalin's Red Army, reaching the gates of Leningrad, Moscow, and Sevastopol. But not all of this vast army was German; indeed by the summer of 1942 over 500,000 were Romanians, Italians, Hungarians, Slovaks, and Croatians – Hitler's Axis allies. As part of the German offensive that year, more than four allied armies advanced to the Don only to be utterly annihilated in the Red Army's Saturn and Uranus winter offensives. Hundreds of thousands were killed, wounded, or captured and the German Sixth Army was left surrounded and dying in the rubble of Stalingrad. Death on the Don tells the story of one of the greatest military disasters of the Second World War.