Here's What You Need to Remember: The Russo-German War was no ordinary conflict fought over territory or resources. For Nazi Germany, it was a war of extermination and subjugation that would have killed the Russian people or reduced them to slavery. For the Soviet Union, it was a war of survival.

In October 1941, the Second World War teetered on a knife edge.

There was war in China and war in North Africa, and soon there would be war between America and Japan. But in the autumn of 1941, the only war that really seemed to matter was fought in a portion of central Russia.

Operation Barbarossa, the German invasion of the Soviet Union, had begun brilliantly on June 22, 1941. Encirclement after encirclement had inflicted almost 4 million casualties on the huge but disorganized Soviet armies. By early October, they had advanced to within 200 miles of Moscow. Now came Operation Typhoon, the offensive to seize the Soviet capital and—or so the Germans hoped—end the campaign.

Desperation breeds optimism, so indeed Germany needed to end the War in the East soon. The newsreels of vast columns of bewildered Soviet prisoners may have conveyed an image of German invincibility, but for the Wehrmacht, Russia was Death by a Thousand Cuts. Germany and its allies had committed more than 3 million men to Barbarossa: by October, they had suffered more than 500,000 casualties, or 15 percent of the invasion force. The panzers sweeping 500 miles deep into Russia left a trail of  broken-down tanks. The Russian roads, few in number and poor in quality, had devoured perhaps 40 percent of the German truck fleet. That left railroads as the supply arteries on the Eastern Front, yet Russian railroad tracks were wider than German ones, stranding supply trains that couldn't move forward until repair crews modified the Russian rails. German logistics collapsed, leaving the troops short of food, ammunition and especially fuel for the panzers.

Not that the Soviets were in any better shape. Its officer corps decimated before the war, and its generals often incompetent but politically acceptable toadies, the Red Army had been caught by surprise and then relentlessly pounded by an opponent that conquered France in just six weeks. But at least the Soviets were falling back on their supply bases. The Red Army was also infused with an endless stream of fresh division after fresh division. The troops were poorly trained and led to be sure, but German intelligence, convinced that the Soviets should have collapsed by now, couldn't understand how the Red Army could take such a pounding and yet keep growing.

Operation Typhoon was like a boxing match between two battered and bloodied fighters barely on their feet. The Soviets could field more than a million soldiers and a thousand tanks at Moscow, dug into multiple defensive lines dug by women and children. The Germans managed to muster almost two million men, and more than a thousand tanks and five hundred aircraft. The plan was do more of what had already worked so well: conduct a series of pincer operations to surround and destroy the Soviet armies in front of Moscow, and then roll into the capital. The fast-moving panzers would be the arms of the pincers, encircling the enemy to keep them from escaping until the footslogging German infantry caught up with the armor and mopped up the pocket. When the Wehrmacht reached Moscow, the city would also be encircled and captured.

With proper supply and good weather, such a big German strike force could probably have conquered any country in the planet. Alas, neither condition would prove true. The initial phase of Typhoon went according to plan, with four Soviet armies and more than 500,000 Soviet soldiers killed or captured at Vyazma alone.                 

But then rain and melting snow fell in early October, bringing with them the infamous rasputitsa, the muddy season that turned the Russian landscape into such a quagmire that vehicles sank to their axles. They had to be hauled out by teams of sweating soldiers whose boots also disappeared into the glutinous morass. Not only couldn't the combat troops advance, but neither could the supply trucks. Meanwhile, Soviet counterattack after Soviet counterattack, even if repelled, left German forces battered and exhausted.

Also unpleasant were the Soviet T-34 tanks. More heavily armed and armored than their Teutonic counterparts, the Germans gasped in dismay as their anti-tanks weapons bounced off the T-34's thick hide. To make matters worse, the T-34 had wide tracks, which gave it better maneuverability in the mud.

But the Wehrmacht still retained the skill, leadership and professionalism that made it the best army in the world at the time. The advance continued, leading Stalin to order the evacuation of the Soviet government from Moscow to Kuibyshev. Despite Stalin choosing to remain in the capital, the move further weakened Soviet morale.

After the German armies paused for breath in early November, the weather turned colder, freezing the mud and giving Hitler's troops the solid footing they needed to advance. By the end of November, German reconnaissance units were just 12 miles from Moscow, so close they could see the towers of the city through their binoculars.

So close and yet so far. By the beginning of December, the thermometer had dropped to 45 degrees below zero Fahrenheit. It's not true that the Germans were unaware of the Russian winter. But with limited supply capacity, priority was given to fuel and ammunition. Besides, who needs winter clothing if Moscow was supposed to be captured before General Winter struck?

Instead, it was the Soviets who struck. Stalin had been reassured by information from Richard Sorge, a German living in Japan but working for Soviet intelligence, that the Japanese would turn south to fight the Americans and British instead of north against Siberia. He felt able to transfer 18 elite Siberian divisions, well-trained and well-equipped for operating in harsh winter conditions, by rail to Moscow.

When the counter offensive began on December 5, the Soviet armies punched through an enemy more scarecrow than human. German weapons were frozen, German soldiers were frozen, and sometimes the soldiers froze to the weapons. The survivors could only watch helplessly as the attackers, warmly clad in fur-lined jackets and boots, and camouflaged in white snowsuits, emerged like ghosts through the mist and snow.

Now came one of those decision points that occur in every major battle. Some of Hitler's generals wanted to retreat to a line far from Moscow. But Hitler feared that a retreat would disintegrate into a panic-stricken rout that would bring the Red Army to the gates of Germany. He ordered his troops to hold their positions to the last man, a hedgehog defense of strong points that would be defended even when surrounded. Though Hitler fired some generals who disagreed, many German commanders later praised the decision as preventing a collapse like that suffered by Napoleon's Grande Armee in 1812.

The Germans were pushed back to Rzhev, 150 miles from Moscow. But their lines were still intact, and though battered, their armies were still ready to fight. And now it was Stalin's turn for overconfidence. The Soviets had also suffered grievously during the counteroffensive: their troops were inexperienced, their supply lines were strained by snow and mud, and they also suffered from the cold. Nonetheless, with dreams of reaching Berlin in his eyes, Stalin ordered his exhausted forces to continue attacking. The result was heavy losses in futile attacks. By February, the Germans even counterattacked, destroying several Soviet divisions.

What had been accomplished? Both sides had gambled and failed. German dreams of capturing Moscow and ending the War in the East had evaporated. Stalin's dreams of a grand counteroffensive that would kick the Germans out of the Soviet Union also faltered. The slaughterhouse that was the Eastern Front would continue into 1942, and then into 1945.

However, it was Hitler's gamble that proved fatal. 1941 and 1942 would be the last years that the Germans had the luxury of waging a one-front war. After that, the Americans and British would open Second Fronts with amphibious landings in Europe and around-the-clock bombing over the Third Reich. If Hitler was to win, it had to be before the Anglo-Americans mustered their strength, and before the Soviets reorganized their armies and harnessed their vast industrial potential.

Ironically, the catastrophe that Germany barely avoided at Moscow only led to catastrophes later on. Hitler may have been right in ordering his armies not to retreat. To the ex-corporal, resentful and suspicious of the German officer corps, this was evidence that he possessed more genius and nerve than the professional soldiers. Therefore Hitler would only listen to himself and never accept the advice of his generals to retreat, which meant the German armies at Stalingrad and Normandy held their positions until they were destroyed.

Would the capture of Moscow have altered the outcome of World War II? Losing their capital has often led nations to seek peace. Moscow was more than the administrative capital of the Soviet Union: it was also a vital rail hub and production center. There was also the symbolic value: totalitarian dictators, like Hitler and Stalin, crafted images of themselves as all-knowing leaders of their nations. Losing Moscow would certainly have dented popular confidence in Stalin. In fact, Stalin apparently did put out discreet peace feelers to Germany through Sweden, which Hitler ignored.