The Battle of Stalingrad began when the German Army drove toward the oil fields of the Caucasus. German commanders saw the reduction of Stalingrad as essential to protecting the left flank of their armies as they drove toward the Caucasus. After heavy, often hand-to-hand fighting, the Germans took most of the city, with enormous casualties to their own forces as well as the Soviets and the civilian population of Stalingrad, by the autumn of 1942. In November of that year, a Soviet army under Georgy Zhukov launched a massive counterattack that encircled the city with the bulk of the German Sixth Army trapped inside. Other German armies in the region were unable to break through the Soviet lines, and a massive assault by Zhukov reduced the Germans to defending themselves by house-to-house fighting. About 300,000 Axis forces surrendered at Stalingrad in February of 1943. Only a tiny fraction of this force ever returned to Germany. Total Axis casualties were about 750,000; and about a million Soviets, many of whom were civilians, were lost as a result of the fighting.