1. Operation Uranus: The Soviet forces launched "Operation Uranus" on November 19, 1942. The Soviet 1st and 2nd Guards armies smashed through Romanian defenses of General Petre Dumitrescu's Third Army north of Stalingrad while the Southwestern Front (General Nikolay Vatutin) did the same to the Romanian Fourth Army south of Stalingrad. The objective of the Soviet assault was to punch through the weakly held Romanian armies and encircle the German Sixth Army.
2. German Sixth Army Trapped: The pincers of the Soviet pincer attack met on November 23 at Kalach-on-Don, west of Stalingrad, encircling the German Sixth Army and the remnants of the Romanian Third and Fourth armies, a total of 300,000 men. The trapped forces included more than 10,000 non-German, mostly Romanian and Italian troops.
3. Hitler Orders "Festung Stalingrad": Despite the encirclement, Adolf Hitler ordered the Sixth Army under the command of General Friedrich Paulus to hold their positions and form a defensive perimeter around Stalingrad, rather than attempting a breakout. The city, therefore, became a "Festung" (fortress) from which there would be no retreat. Hitler believed that the Luftwaffe could adequately supply the forces in Stalingrad until a relief effort could break the encirclement from the outside.
4. Luftwaffe Airlift Insufficient: The Luftwaffe attempted a massive airlift to supply the trapped German forces, but due to the relentless attacks by the Soviet Air Force and bad weather, it failed to supply the 6th Army with the required amount of materials. Only about half of the supplies dropped by air reached the Sixth Army.
5. Soviet Winter Offensive: In November and December 1942, Soviet troops launched several attempts to cut the German pocket into smaller parts and capture the city. While these attacks were held off by the German defenders, they further stretched the German thin supply lines.
6. Operation Winter Storm: In December, the German Army Group Don under the command of Field Marshal Erich von Manstein attempted a relief effort of the trapped Sixth Army, code-named "Operation Winter Storm". The operation initially made progress, but due to stubborn Soviet resistance, lack of supplies, and bitter cold of the Russian winter, it failed to break through.
7. Surrender of the Sixth Army: By early 1943, the situation for the encircled Sixth Army became dire. The soldiers were starving, and there were no chances of breaking the Soviet encirclement. Hitler continued to order the army to hold its position and refused to allow a breakout attempt. Finally, on February 2, 1943, General Paulus surrendered the remaining German forces to the Soviets.
The defeat at Stalingrad marked a turning point in the war. Not only was it a devastating loss of men and equipment for Germany, but it also shattered the myth of German invincibility and boosted the morale of the Allies. The turning point in German fortunes had arrived, and the initiative passed to the Soviet forces.