In the warm predawn darkness of June 22, 1941, three million men waited along a front hundreds of miles long, stretching from the Baltic coast of Poland to the Balkans. Ahead of them in the darkness lay the Soviet Union, its border guarded by millions of Red Army troops echeloned deep throughout the huge spaces of Russia. This massive gathering of Wehrmacht soldiers from Adolf Hitler's Third Reich and his allied states - notably Hungary and Romania - stood poised to carry out Operation Barbarossa, Hitler's surprise attack against the country of his putative ally, Soviet dictator Josef Stalin.

At precisely 1:00 am that morning, the radios of command and headquarter units all along the line crackled to life. Officers and generals heard a single code word: "Dortmund" for Army Group North, and "Wotan," the name of the one-eyed pre-Christian god of knowledge, war, and runes, for Army Group South. In answer to shouted orders and tactical-level radio transmissions, men threw aside camouflage nets, truck, halftrack, and panzer engines started with a throbbing rumble, and artillerists prepared their weaponry for the terrific barrage generally preceding a Wehrmacht assault. Soldiers swarmed onto trains, and the propellers of thousands of German aircraft, including the still-formidable Stuka dive-bombers, roared amid the nighttime stillness on dozens of airfields throughout Eastern Europe.

The Soviets were so caught by surprise at the start of the attack that the Germans were able to push several hundred miles into Russia across a front that stretched dozens of miles long, reaching the major cities of Leningrad and Sevastopol in just three months. The first major Russian city in their path was Minsk, which fell in only six days. In order to make clear his determination to win at all costs, Stalin had the three men in charge of the troops defending Minsk executed for their failure to hold their position. This move, along with unspeakable atrocities by the German soldiers against the people of Minsk, solidified the Soviet will. In the future, Russian soldiers would fight to the death rather than surrender, and in July, Stalin exhorted the nation, "It is time to finish retreating. Not one step back! Such should now be our main slogan...Henceforth the solid law of discipline for each commander, Red Army soldier, and commissar should be the requirement - not a single step back without order from higher command."

Though the attack caught Stalin utterly by surprise, the tension between the two violent, predatory states made such a clash almost inevitable. The USSR had no plans to invade Germany in 1941, but it had remained an aggressive military state infused with the savage zeal to abolish all borders into one international "workers' paradise" through force of arms, as Vladimir Lenin (and many other Soviet leaders and writers) made clear. Hitler, for his part, wanted Lebensraum for the Germans - at the expense, of course, of the Slavs - and viewed the communist state as an existential threat to Europe itself. Driven by a mix of raw acquisitive ambition, ideology, and actual understanding of the Soviet Union's own minatory intent, the Fuhrer launched a full-scale invasion. Likely with intentional malice, the declaration of war delivered by Gustav von Schulenburg several hours after the invasion's start mirrored almost exactly the Soviet pretext of "defending their borders" used during the USSR's invasions of Poland, Latvia, Lithuania, and Finland.