Well, everyone's answer was correct and the bits of info already assembled are pretty on-spot
serves me for picking an easy start
Stalingrad Grain Elevator
The elevator was the highest building in the southern district of Stalingrad, and simultaneously it was the most weakly defended district, defended by weakened 35th Guards and 131 Infantry divisions. After the Germans tried their first strike agains the elevator on 14th September 1942, the command reinforced the district with the 92nd Special Infantry Brigade which consisted of naval infantry from the Northern Fleet on 18th September, just a day after the Germans started a massive offensive against the building, trying to capture it as a strategic point. The elevator would become a place where battle would not cease for a day, just varying in intensity from "constant machinegunning" to "shooting once every hour", and it would last from the 17th till the 23th September - almost a whole week.
It was a critical point, giving oversight of the whole place and also total control over the "Stalingrad-2" cargo railway terminal. The elevator itself was defended by just around 60 men: naval infantry fought very hard and upon arrival managed to quickly cleanse several streets from the Nazis.
On 19th September the German troops once again tried taking the elevator, in two consecutive attacks, supported by 7 tanks. 45 Soviet soldiers under the command of A.S. Polyakov managed a counterstrike, killing around 30 of the attackers. One of the defenders recalled:
"The grain in the building caught fire. Water was evaporating in the machine gunes, the wounded asked for water but we had none. We defended the elevator for three days and three nights non-stop."
This set the Nazis back for a while, but on 21st September they tried storming the highpoint again, this time taking several bombers to ravage the elevator, as well as using mortars and 16 tanks as a support. During this day, a total of 7 attacks happened and all were averted by the defenders. The fights were very tense - often the Germans and Russians were fighting for a single story of the large building.
"...The fight for the elevator rages on. The Russians are pouring fire from everywhere. We're in the basement of a house, we cannot get up on the street... our entire battalion is less than a company in strength. Such ferocious fights no soldier of ours can recall. If all houses in Stalingrad would be defended as ferociously, none of us will ever see Germany again"
wrote one of the German soldiers - Wilhelm Hofman of the 267 infantry regiment of the 94th division - in his daily notes - he later was killed in a street fire, ironically proving his statement.
On 22nd of September the strain finally got the defenders. The ammunition and food supplies ran out, many defenders of the elevator were killed or wounded. However, for many hours they continued to fight, before finally abandoning the place.
It was recaptured in a similar ferocious battle, even if slightly faster, once again - by the Soviet naval infantry troops on 24th January, 1943. By the end of the fight, the elevator was pierced by gunfire in almost any place imaginable. In 1977, a memorial dedicated to the fierce fight for the elevator was erected there, depicting a naval infantryman.
The German POWs in a photo near the recaptured ravaged elevator: