Final answer:
The German advance into the Soviet Union was halted by the Battle of Stalingrad and the harsh Russian winter. The Battle of Stalingrad resulted in the surrender of the German Sixth Army and marked a turning point in the war. The Russian winter immobilized German forces and made it difficult for them to sustain their advance.
Step-by-step explanation:
The German advance into the Soviet Union was stopped primarily due to two factors: the Battle of Stalingrad and the harsh Russian winter. In the Battle of Stalingrad, the Soviet Red Army launched a successful counterattack and managed to trap the Germans, leading to the surrender of the German Sixth Army. This defeat marked a turning point in the war and put Germany on the defensive for the remainder of the conflict.
In addition, the Russian winter played a significant role in stopping the German advance. The bitter cold and severe winter conditions were not anticipated or prepared for by the German forces.
German soldiers lacked appropriate winter clothing and supplies, and their vehicles and machinery, including tanks, became immobilized. These factors, coupled with the challenges in maintaining supply lines, forced the German army to halt their advance and ultimately retreat.