Birth of urban warfare

Russian troops fighting in the ruins of Stalingrad, Russia, 1942

Quite an interesting read if you're interested in history nature of warfare. Battle for Stalingrad, World War II, noted as one of the most important turning points of the war.

From wikipedia:

German military doctrine was based on the principle of combined-arms teams and close cooperation between tanks, infantry, engineers, artillery and ground-attack aircraft. To counter this, Soviet commanders adopted the tactic of always keeping the front lines as close to the Germans as physically possible; Chuikov called this "hugging" the Germans. This forced the German infantry to either fight on their own or risk taking casualties from their own supporting fire; it neutralized German close air support and weakened artillery support.

The Soviets understood that, in Stalingrad, the best defense would depend on anchoring their defense lines in numerous buildings overseeing strategically important streets and squares. Such a strategy would hold for as long as possible all the ground the Soviets could take in the city. Thus, they converted multi-floored apartment blocks, factories, warehouses, street corner residences and office buildings into strongholds bristling with machine guns, anti-tank rifles, mortars, mines, barbed wire, snipers and small 5-10 man units of submachine gunners and grenadiers prepared for house-to-house combat.

Bitter fighting raged for every ruin, street, factory, house, basement and staircase. The sewers were the sites of labyrinthine firefights. The Germans, calling this unseen urban warfare Rattenkrieg ("Rat War"), bitterly joked about capturing the kitchen but still fighting for the living room and the bedroom. In such desperate chaos, all battle lines vanished, and the major, armor-supported mobility to which the German soldiers were accustomed degenerated into vicious, fast-paced skirmishes ranging through bombed-out debris of residential neighborhoods, office blocks, basements and apartment high-rises. Some of the taller buildings, blasted into roofless shells by earlier German aerial bombardment, saw floor-by-floor, close-quarters combat, with the Germans and Soviets on alternate levels, firing at each other through holes in the floors.

Fighting on Mamayev Kurgan, a prominent hill above the city, was particularly merciless, and the position changed hands many times. By 12 September, the Soviet 62nd Army had been reduced to 90 tanks, 700 mortars and just 20,000 men.

The 13th Guards Rifle Division, assigned to retake Mamayev Kurgan and Railway Station No. 1 on 13 September suffered particularly heavy losses. Over 30 percent of its soldiers were killed in the first 24 hours, and just 320 out of the original 10,000 survived the entire battle. Both objectives were retaken, but only temporarily. The railway station changed hands 14 times in six hours. By the following evening, the 13th Guards Rifle Division had ceased to exist, but its men had killed approximately an equal number of Germans. Combat raged there for weeks near the giant grain silo. When German soldiers finally took the position, only forty dead Soviet fighters were found, though the Germans had thought there were many more due to the ferocious resistance. The Soviets burned heaps of grain during their retreat.

In another part of the city, a Soviet platoon under the command of Yakov Pavlov turned an apartment building that oversaw a square in the city center into an impenetrable fortress, later called "Pavlov's House". The soldiers surrounded it with minefields, set up machine-gun positions at the windows and breached the walls in the basement for better communications. The soldiers found about ten Soviet civilians hiding in the basement. They were not relieved, and not significantly reinforced, for two months. Well after the battle, Chuikov liked to joke that more Germans died trying to capture Pavlov's House than died capturing Paris. According to Beevor, throughout the second month, after each wave of German assault against the building, the Soviets had to run out and kick down the piles of German corpses in order for the machine and anti-tank gunners in the building to have clear firing lines across the square. The building was labeled Festung ("Fortress") on German maps. Sgt. Pavlov was awarded the Hero of the Soviet Union for his actions.
Soviet marines landing on the west bank of the Volga River.

With no end in sight, the Germans started transferring heavy artillery to the city, including the gigantic 800 mm (31.5 in) railroad gun nicknamed "Dora", but made no attempt to send a force across the Volga, allowing the Soviets to build up a large number of artillery batteries on the east side. This artillery continued to bombard the German positions. German tanks became useless amid heaps of rubble up to eight meters high.

Snipers on both sides used the ruins to inflict heavy casualties. The most famous Soviet sniper in Stalingrad was Vasily Zaytsev with 225 confirmed kills during the battle. Zaytsev was one of a whole corps of snipers and had over thirty students, who were credited with killing over three thousand German soldiers during the war.

For both Stalin and Hitler, Stalingrad became a matter of prestige beyond its strategic significance. The Soviet command moved the Red Army's strategic reserves from the Moscow area to the lower Volga, and transferred aircraft from the entire country to the Stalingrad region.

The strain on both military commanders was immense: Paulus developed an uncontrollable tic in his eye, which eventually afflicted the left side of his face, while Chuikov experienced an outbreak of eczema that required him to have his hands completely bandaged. Troops on both sides faced the constant strain of close-range combat.

After three months of slow advance, the Germans finally reached the river banks, capturing 90% of the ruined city and splitting the remaining Soviet forces into two narrow pockets. Ice floes on the Volga now prevented boats and tugs from supplying the Soviet defenders. Nevertheless, the fighting, especially on the slopes of Mamayev Kurgan and inside the factory area in the northern part of the city, continued as fiercely as ever. The battles for the Red October Steel Factory, the Dzerzhinsky tractor factory and the Barrikady gun factory became world-famous.

From historyofwar:

On August 23, 1942, precisely at 18:00, one thousand airplanes began to drop incendiary bombs on Stalingrad. In that city of 600,000 people, there were many wooden buildings, gas tanks and fuel tanks used for industrial purposes. Stalingrad was heavily hit by air attack; one raid of 600 planes started vast fires and killed 40,000 civilians. By then, the 6th Army was in the Stalingrad suburbs and had taken the bank of the River Don just north of the city, while German tanks from the 14th Panzer Division approaching the Volga in the south. With the 62nd Army not even in the city at that point, the first German attacks were taken by a single division of NKVD and some workers from the city tractor factory. OKW, concerned about the inadequacy of the forces protecting the 6th Army's flanks, advised a withdrawal be undertaken from Stalingrad to consolidate the line and prevent the army being cut off by an enemy breakthrough. Hitler instead transferred units away from the Don sector to the 6th Army and ordered it to capture the city.

When the Germans entered Stalingrad, they saw nothing but ruins, however their advance was frustrated as thousands of micro battles erupted all over the streets of what used to be a city. Resistance was fierce but the German forces eventually managed to occupy a large part of the northern bank by the middle of September, backed by the aircraft of Luftflotte IV. "The Germans obviously thought that the fate of the town had been settled," wrote Vasily Chuikov, the commander of the 62nd Army who had replaced Lopatin on 10 September. "We saw drunken Germans jumping down from their trucks, playing mouth organs, shouting like madmen and dancing on the pavements." They penetrated to within two hundred yards of his command post. Still the Soviets fought on and the Germans continued to meet resistance in the streets of Stalingrad. It broke down to battalion, company and platoon engagements, usually at close quarters. A German general said: "The mile, as a measure of distance, was replaced by the yard ..."

General Chuikov threw in every last reserve he had. By the middle of November the 6th Army had cut through Stalingrad, cutting the 62nd Army in two parts. But that still did not mean the end of it. Shrinking into an ever smaller perimeter, the Red Army was fighting stubbornly. Particularly severe clashes took place over Mamayev Kurgan on Hill 102, which changed hands at least eight times. One house in Stalingrad was defended by a single platoon under Sergeant Pavlov. That house, known as "Pavlov’s house", became a symbol of determination of Soviets to hold the city no matter what. Completely surrounded by Germans, Pavlov’s soldiers were holding the constantly attacked house until the relief came. The battle raged for fifty-nine days. As an illustration of the see-saw nature of the fighting, the diary of 62nd Army, described the intensity of fighting for the Central Station in Stalingrad, which changed hands fifteen times, four times in one day: "0800 Station in enemy hands. 0840 Station recaptured. 0940 Station retaken by enemy. 1040 Enemy ... 600 meters from Army command post … 1320 Station in our hands."

At the Central Station, a battalion of Soviet Guardsmen dug in behind smashed railroad cars and platforms. Bombed and shelled, the survivors moved to a nearby ruin where, tormented by thirst, they fired at drainpipes to see if any water would drip out. During the night, German sappers blew up the wall separating the room holding the Soviets from the German-held part of the building and threw in grenades. An attack cut the battalion in two and the headquarters staff was trapped inside the Univermag department store where the battalion commander was killed in hand-to-hand fighting. The last forty men of the battalion pulled back to a building on the Volga. They set up a heavy machine-gun in the basement and broke down the walls at the top of the building to prepare lumps of stone and wood to hurl at the Germans. They had no water and only a few pounds of scorched grain to eat. A German tank ground forward and a Russian slipped out with the last antitank rifle rounds to deal with it. He was captured by German machine gunners. He persuaded his captors that the Soviets had run out of ammunition, because the Germans moved out of their shelter. The last belt of machine-gun ammunition was fired into them and an hour later they led the anti-tank rifleman on to a heap of ruins and shot him. More German tanks appeared and reduced the building with point-blank fire. At night, six survivors of the battalion freed themselves from the rubble and struggled to the Volga.

The Luftwaffe was making up to 3,000 sorties a day. The Germans had superiority in airpower and artillery. To neutralize it, General Chuikov directed his troops to "hug" the Germans, to remain in a close combat so that German commanders could not use air strikes without endangering their own men. The 62nd Army was practically on its own, the Red Army finding it difficult to help with supplies and replacements. Any that reached the city had to cross the Volga River under German fire. The survivors of those crossings said some days the river was red with the blood. The whole battle was a nightmare for the both sides. The Germans assaulted the Red October factory on 27 September and occupied the northern landing stages on 5 October. Despite a huge Soviet bombardment the Germans managed to take the Tractor Plant on 16 October and parts of the Barricades Gun Plant on the 23 October.

The fighting never stopped. It could slow down at times, and then erupt with new energy at any time of the day. With all the technology and equipment involved, there were close quarters and hand-to-hand fights all over Stalingrad. Soviets practiced night attacks on the isolated German units. They would use knives and bayonets in such fighting. None of the armies of WWII were really trained for, or expected that kind of warfare. Perhaps, that type of fighting suited the fatalistic Soviets better than the Germans. Germans who fought on the Eastern Front often remarked that Soviets found some inspiration in close combat, and in desperate situations fought with some crazy passion. And Stalingrad definitely seemed to be a desperate situation for the Soviets, surrounded and outnumbered in the ruins of what used to be a city.

The intensity of fighting can be gauged from what one German Leutnant wrote: "We have fought during fifteen days for a single house. The front is a corridor between burnt-out rooms; it is the thin ceiling between two floors ... From story to story, faces black with sweat, we bombard each other with grenades in the middle of explosions, clouds of dust and smoke, heaps of mortar, floods of blood, fragments of furniture and human beings ... The street is no longer measured by meters but by corpses ... Stalingrad is no longer a town. By day it is an enormous cloud of burning, blinding smoke; it is a vast furnace lit by the reflection of the flames. And when night arrives, one of those scorching howling bleeding nights, the dogs plunge into the Volga and swim desperately to gain the other bank. The nights of Stalingrad are a terror for them. Animals flee this hell; the hardest stones cannot bear it for long; only men endure."

Coming shortly after Rommel's defeat at El Alamein and the Allies making landings in Algeria and Morocco (Operation Torch) in early November, on 19 November 1942 a Russian counter-offensive began (codednamed Operation Uranus) under the overall command of Marshal Georgii Zhukov. Zhukov had decided to hold Stalingrad with the minimum amount of troops necessary and concentrate his reserves on the weaker Axis forces protecting the 6th Army's flanks, something OKW had foreseen. The Axis forces, chiefly the 3rd and 4th Romanian Armies, surrounding Stalingrad were taken by surprise and could not contain the attack. On 23 November the two wings of the Red Army met. The German 6th Army and elements of the 4th Panzer Army, about 220,000 men, were trapped in a pocket 35 miles wide and 20 miles from north to south. OKW begged Hitler to allow the 6th Army to breakout to the west while the Soviet lines were still not firmly established but Reichsmarschall Hermann Goring boasted he could fly in 500 tons of supplies a day and keep the 6th Army going as an effective fighting force. Hitler seized on this and ordered Paulus to fortify his positions and await a relief. Meanwhile the Soviets struck further south too, and forced the 17th Army and 1st Panzer Army to withdraw and despite trying to cut Army Group A in the Caucasus, appalling weather allowed the Germans to retreat steadily both northwards towards Rostov and westwards back towards the Kerch Straits where 17th Army formed a large bridgehead on the Taman Peninsula. This was gradually pushed back but the vast majority of 17th Army escaped back into the Crimea across the straits.

A valiant relief effort, codenamed Operation Winter Storm, was launched by General Erich von Manstein's Army Group Don on 12 December 1942. The force included the 4th Romanian Army, and the Hoth Group with the 6th, 17th and 23rd Panzer Divisions. It had managed to advance to within thirty miles of the city by 21 December 1942, but faced strong resistance by the 5th Shock and 2nd Guards Armies. Manstein took it upon himself to order Paulus to breakout to the southwest and link up with Army Group Don but Paulus refused to move without a direct order from the Fuhrer and the 6th Army remained trapped around Stalingrad. The Soviets launched Operation Little Saturn on 24 December 1942 to further isolate Stalingrad from the main German forces. On 9 January 1943 the Soviets began to drive on the centre of the city but found that the tables had now been reversed. They would be the ones to attack every house, every building and fight for every room. The Luftwaffe managed to keep the 6th Army supplied (although it was never really enough) until quite close to the end and airlifted over 30,000 troops out of the pocket. Finally, on February 2, Field Marshal von Paulus surrendered, with 23 generals, 2500 other officers and 90,000 soldiers. Only some 6,000 would live to see Germany again.