I've often read about Stalingrad, but one piece of info eludes me. At the time of their surrender, the Germans were reduced to 2 'pockets'. How big were they in terms of area?
The most detailed map, I was able to find, is here.
As you can see both "pockets" at the time of a surrender had area of only a few square kilometers.
However, by the 25th January (the last day the 6th German army had a continuous front line) the area under German control was still upto 100 square kilometers. In the morning of the 26th January the Red army started the new wave of a massive offence along the whole front line, which not only resulted in the occupying of the Mamayev Kurgan and nearby territories (which effectively meant that the German XI corps wasn't longer connected to the rest of the army - "Northern pocket"), but also led to other significant advances, so the area under German control was almost halved at the end of the day. Nonetheless, the fierce fights were going for at least four days more - 27-30 January.
"South" (Paulus) capitulated on the 31st January, while holding only few blocks in the city center. "North" (Strecker) still resisted, so it was set under heavy artillery fire until the surrender (2nd February).