The decision to invade the Soviet Union was, in large part, economic. Germany needed the Soviet Union's agricultural resources, manufacturing capability, and oil fields for its own people and intended to enslave the Soviet people for German industry. Although ideology fired a huge part of the recruiting and strengthening of the German armed forces and it was understood by many that the Soviet Union and its Communism would eventually become a target, the invasion, from a military point of view, was more about resources than about government and way of life.

The invasion was originally scheduled to begin on May 15, 1941, in an effort to make as much progress as possible before the harsh Russian winter hit. Many German commanders believed the Soviet Union wouldn't put up much of a fight and that the invasion would take ten weeks at the most. However, Hitler was forced to postpone it until June 22 because Germany had to help Mussolini take Greece and intervene in Yugoslavia when negotiations between that nation and the Soviet Union threatened the southern flank of German operations.

Early Warnings

Thanks to both Soviet and British intelligence, Hitler's plans were known well in advance. But Stalin refused to let his military commanders prepare for a German invasion in the belief that a lack of Soviet provocation would placate Hitler and prevent or at least delay an assault. Stalin's unwillingness to prepare cost his country greatly.

Hitler didn't even try to be subtle as he massed his army at the western borders with the Soviet Union. At 3:00 A.M. on June 22, German troops invaded across a front extending from the Arctic Sea to the Black Sea — a line some 1,500 miles long. As with earlier invasions, the Luftwaffe flew ahead of the ground forces, bombing strategic Soviet airfields and engaging Soviet fighters in combat. More than 400 Soviet planes were shot out of the sky, and twice that number were lost on the ground. Only about 35 German planes were lost during the first day's fighting.

The invading force made excellent use of its artillery, softening up the opposing army as it proceeded forward. Interestingly, most of the 7,200 pieces were drawn by horses rather than trucks because they could handle the rocky terrain better and didn't need gasoline. In total, the invasion included 3,350 German tanks, 600,000 other motor vehicles, and 625,000 horses. The Luftwaffe air fleet consisted of 2,770 bombers.

Germans Plow Onward

Germany quickly gained air superiority, and the invaders often found themselves aided by a supportive populace, most notably in the Baltic republics and the Ukraine. (However, atrocities committed by the Germans against the local populations quickly turned Soviet sympathizers against them, resulting in ongoing guerrilla warfare.) Soviet defensive lines were quickly annihilated by the German blitzkrieg, and Minsk fell on June 28, followed by Smolensk on July 10, and Kiev on September 27.

One of the longest battles occurred at Leningrad, the Soviet Union's second largest city. Hitler initially wanted to give the city to Finland, which at the time was fighting on Germany's side. But Finland wanted only the border it had before the 1939 Soviet invasion and refused to push farther. Ultimately, Hitler decided to level Leningrad, which he insisted on calling by its former name of St. Petersburg. In a September 29 communiqué to his generals, Hitler said: “The Führer has decided to have St. Petersburg wiped off the face of the earth. The further existence of this large city is of no interest … for the problem of the survival of the population and of supplying it with food is one which cannot and should not be solved by us.”

Leningrad Surrounded

German forces surrounded nearly all of Leningrad in August 1941 and immediately severed its rail link with Moscow. When an assault on the city failed, German forces laid siege, bombarding the city of 3 million with artillery and aircraft. Food quickly grew scarce, and people starved by the thousands. The only supplies came from Novaya Ladoga across Lake Ladoga, a sixteen-hour voyage by barge. Supplies arrived at the port city of Osinovets and were transported by rail to Leningrad. The barges were easy targets for German bombers (twenty-four were sunk during the first two months of the siege), and the food that arrived could feed only a small percentage of those who needed it. Soviet naval forces used the route to evacuate nearly half a million refugees, though thousands stayed behind to defend the former Russian capital.

Soviet soldiers in Leningrad fought the Nazis with all they had, desperate to break the siege and turn their defense into an offense. However, they were unable to breach the German lines and open supply routes until January 1943. By then, hundreds of thousands of people had died of starvation or from the constant German bombardment.

The Battle of Moscow

Equally important was the battle of Moscow, code-named Operation Typhoon, which began October 2, 1941. The Germans made great strides during the early days of the battle, taking 650,000 prisoners, and by mid-October were just 60 miles from the city. But again, the delay of the initial invasion hampered German progress.

The night of October 6, 1941, snow began to fall. It melted the next morning, turning the roads into muddy bogs that slowed the German military advance as heavy equipment sank axle-deep in muck. Moscow, once so close, now seemed a long way off. German commanders asked Berlin for winter clothing, just in case the invasion took longer than originally believed.

The weather wasn't the only thing that adversely affected the German invasion of Moscow. On October 10, Marshal S. K. Timoshenko was relieved as commander of the western strategic sector by Marshal Georgi Zhukov. The Germans saw little importance in this move, but Zhukov was a skilled strategist who had organized the defense of Leningrad. He had arrived to save Moscow.

Zhukov based his defensive strategy on the one factor the German invaders had not counted on: the Soviet Union's muddy, almost impassible roads, and the impending Russian winter. The first sign of winter came on November 6 when temperatures fell below freezing and stayed there. The Germans, initially pleased with the cold temperature because it would freeze the mud, soon found themselves at its mercy because of a lack of cold-weather clothing, portable heaters, and winterizing machinery lubricants.

Still, the Germans attempted to press on toward Moscow. On November 30, combat engineers came within 10 miles of the city, though the main combat force was 50 miles behind them. The Germans were attacked by Soviet tanks and cavalry, which were able to traverse the frozen roads quite well. On December 4, the Germans realized that they simply could not compete with the vicious Russian winter and initiated a pullback from Moscow. It was the Russian cold that had also halted Napoleon's invasion of Russia in 1812.

Hitler, against the advice of his military advisers, ordered the army to make one last push into Moscow. His goal was the destruction of the Kremlin as proof to the Soviet people that Communism was dead. The attack was launched on December 7 amid a growing snowstorm and winter darkness. A handful of infantry managed to make it to the outskirts of the city but were driven back by Soviet soldiers assisted by workers armed with hammers, clubs, and whatever else they could find. By the time Hitler authorized a pullback, the temperatures had dropped to twenty-eight degrees below zero. Moscow was saved.

Other German-Soviet Fronts

Germany's Soviet offensive continued on a number of other fronts, with the Germans winning strategic victories the next summer in Ukraine, at Sevastopol in the Crimea, and elsewhere.

By November 1942, German forces were on the verge of taking Stalingrad, one of the nation's largest industrial cities and the gateway to the Soviet oil fields. General Friedrich Paulus, commander of the Sixth Army, was given the job of bringing the city under German control, a task that proved more difficult than anticipated.

Paulus and his army started the attack August 21 and quickly fought their way to the city's outskirts, where they faced extremely heavy fighting.

Paulus laid siege to Stalingrad on September 12. Throughout the long siege, the Germans used bombers and artillery to destroy as much of the city as possible, but the defending Soviets under General Vasily Chuikov refused to give up. Eventually, the Germans were reduced to fighting building to building in an attempt to rout the entrenched Soviet soldiers.

Then General Zhukov implemented a counterattack that started with a Soviet assault within the city on November 19 while additional Soviet forces surrounded the German army at Kalach. When the Soviet pincers closed, the Sixth Army and much of the Fourth Panzer Army were trapped. General Paulus probably could have broken out early in the counterattack but was ordered by Hitler to defend his position at Stalingrad based on assurances that the Luftwaffe would be able to deliver plenty of supplies and reinforcements to the trapped army of nearly 284,000 men.

It quickly became apparent that Goering had dramatically overstated the Luftwaffe's capabilities. In fact, it was physically impossible for the German air force to deliver sufficient supplies to the trapped forces; on its best days, it was able to drop just eighty tons of food and equipment — far less than what was needed.

Paulus's men fought with all they had, but the Soviet squeeze grew tighter by the day and the German force was quickly decimated by the cold and the lack of food and supplies. Wounded soldiers had their rations slashed or eliminated so available food could be used to feed those able to fight. On January 22, Paulus sent a radio message to Hitler: “Rations exhausted. Over 12,000 unattended wounded in pocket. What orders should I give to troops who have no more ammunition and are subjected to mass attacks supported by heavy artillery?”

Hitler's response: “Surrender is out of the question. The troops will defend themselves to the last.”

German Army Suffers Heavy Losses

The Germans continued to fight, but the battle was all but over as Russian forces closed in. Paulus, who was promoted to field marshal by Hitler on January 30, surrendered his headquarters on January 31, becoming the first German field marshal to do so. Sporadic fighting by German troops continued around Stalingrad until February 2, 1943.

The Battle of Stalingrad took a tremendous toll on the German military machine, as did the entire Soviet offensive. More than 140,000 German soldiers lost their lives at Stalingrad, with another 91,000 taken prisoner. Germany also lost a huge number of planes and other equipment — material it could ill afford to lose at that point in the war.

Having spent so much time defending itself against Germany, the Soviet Union was now poised to launch a major offensive.