The Battle of Stalingrad was considered to be the turning point of the eastern front in World War II in favor of the Soviets. Prior to the Battle of Stalingrad, the Wehrmacht had been taking Soviet ground, and Hitler wanted to take the city because of its symbolic value. The battle taking place in winter ensured that German supply lines deteriorated.
The German army had higher-quality training and equipment than the Soviet army did, but its soldiers were unprepared for the Russian winter. Stalingrad's strategic position near the Volga River made it a valuable asset, and Stalin sent over a million troops there. They held the city for six months, finally driving the Germans out in January of 1943 when the winter became too brutally cold for supply lines to be maintained. A miscommunication among the Luftwaffe also prevented supplies from reaching the Sixth Army, instead allowing the Soviet army to regroup.
The German army attempted to use its blitzkrieg strategy of swift and sudden force, but it was not effective, partially because of the closeness of an urban environment making it difficult to maneuver tanks. The loss of the Battle of Stalingrad shook the Wehrmacht's morale and bolstered the Soviets' to the point that they began retaking land that the German army had previously occupied.