I agree 100%
This is Stalingrad.
"The point of these observations is that the Soviets had no opportunity to grasp the nature of extended urban warfare or explore the inherent defensive potential of cities.
Either cities were defended in their surrounding fortifications, as in Odessa, Sevastopol, Tula, and Leningrad, or they were taken relatively quickly as part of a larger campaign, as was Kiev. The closest the Soviets came to their later achievements at Stalingrad were the individual feats of courage and resistance in the face of certain annihilation that Soviet soldiers exhibited at the fortress of Brest-Litovsk on the Soviet western frontier, and in the fortifications around Sevastopol.
Stalingrad thus represented something new for the Soviets—an object lesson in the advantages defenders have when fighting inside large cities, and a laboratory in which to develop the tactics of urban warfare so sadly neglected in the interwar period."
"
Something had clearly changed. Stalingrad was defended in the streets of the city itself, as Odessa and Sevastopol had not been, and the Wehrmacht found this much tougher going. The Soviet 62nd and 64th armies in Stalingrad itself faced a horrific and desperate struggle not to be driven into the Volga, but they would exact a terrible toll on the German troops they faced. What, tactically, was happening?
The Soviets were clearly adapting well to the strains of urban warfare, at least as well as the Germans, and their experience in Stalingrad repays closer attention."
You can read all this
right here and you can see how different Stalingrad was compared to all the other major battles before it.
