Barbarossa Day. The German invasion of the Soviet Union begins. Not of Russia or of what was then Ukraine but of the Soviet Union or, in other words, eastern Poland that the Red Army had invaded in 1939. Did Hitler make a mistake by the invasion itself? It did not look like it at first as the Wehrmacht rolled ahead and Stalin and his gang were caught "unawares" despite the many warnings. Nevertheless, it was his big mistake or, to be precise, the conduct of the war in the east was.