We don't often associated the use of tanks with the battle for Stalingrad (now Volgograd). The image brought to mind is one of suffering infantry, freezing, starving, lice ridden.
But this episode illustrates that tanks from both the Russian and German sides were deployed during the German advance on the city. And the first Russian tanks we see are not the usual T-34s, which were probably the best medium tank of the war. These are heavy tanks, the Russian KV with adequate fire power and armor that was impenetrable to any tank-mounted German cannon.
In their first engagement, in a village on the Don River, the Soviets used their usual tactics. Ka-Boom -- a headlong rapid plunge of everything they had, like a sledgehammer blow. In the village, both sides ran into the disadvantages of urban warfare -- straight, narrow streets in which maneuver was impossible, buildings from which weapons could be fired, and crossroads that seemed designed for ambushes. The outnumbered and clumsy Russian tanks were wiped out.
At the gates of Stalingrad, the Germans, reckoning that the city was an industrial center, bombed it thoroughly and reduced it to rubble, making the same mistake that the Allies made at Cassino. The shattered building and the mounds of concrete and stone that filled the streets almost precluded the use of tanks and, if anything, provided better cover for the defenders.
One of the more effective anti-tank weapons of the Russians was a very large rifle. It looks puny compared to, say, a bazooka or a Panzerfaust or Piat, yet the velocity and mass of its bullets enabled it to penetrate the armor of the Panzers.
The Russians, mustering their last reserves, attacked both German flanks and isolated an entire army. Without supplies, without relief, the remaining German soldiers were surrendered. About 90,000 of them became POWs in Russia, and about 5,000 of them ever returned to their homes.
The CGIs are among the best I've seen, extremely detailed and realistic. The format gives both sides an opportunity for talking heads to explain their point of view. An excellent series.