The German assault on Stalingrad, using the 6th Army and elements of the 4th Panzer Army, began in August 1942 and soon deteriorated into brutal close quarters combat as stalemate set in. From their initial incursions into the southern sector of the city, German troops began the slow and arduous process of pushing further into the city, which had been reduced to rubble by artillery fire and constant aerial bombardment. The remaining Soviet forces in Stalingrad were gradually pushed eastwards towards the Volga River where they could receive supplies from barges that crossed from the other side under heavy fire. Soldiers of the Red Army held out for months in their famous last stand in the Tractor Factory and the Red October Factory. As winter set in the river froze making the resupply efforts of the Red Army even harder. The strength of the Luftwaffe began to diminish as losses accumulated over the hundreds of bombing runs it flew to destroy Soviet hiding places within the city.
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