The battle of Stalingrad!

The Battle of Stalingrad (1942–1943) was a decisive clash between Nazi Germany and the Soviet Union. After brutal fighting in the city, the Red Army encircled the German Sixth Army, which was forbidden by Hitler to retreat. Exhausted and without supplies, the Germans eventually surrendered. The defeat was a major turning point in the war: from Stalingrad onward, the Soviet advance toward Germany began.