The Battle of Stalingrad has remained known especially by the extreme intensity of close combat waged between the ruins of an industrial city.
In June 1942, the Germans launched Operation Fall Blau (Case Blue), aiming to capture the oil fields of the Soviet Union's Caucasian region, securing at the same time their flank along the Don and Volga rivers. Stalingrad, a city on the right bank of the Volga, was important for its industry, inland waterway, and railway transport, but also symbolically because it was bearing the name of the Soviet Union's ruler.
The Red Army had suffered since the beginning of Operation Barbarossa losses hard to imagine, but the Soviets still had enough human resources to build up several reserve armies behind the front. On the other hand, the Germans had on their side entire armies from Romania, Italy, and Hungary to compensate for the shortfall of men.
The German offensive for the conquest of Stalingrad began in late August with the 6th Army and the 4th Panzer Army. The Luftwaffe unleashed from the very beginning an intensive bombing campaign, transforming the city into a sea of rubble.
The Soviets organized strongpoints defended with anti-tank weapons and snipers. The combat was waged for every floor, each room, in basements, factories, silos and even in the city's sewer system. Soviet reinforcements were brought permanently from the other bank of the Volga to replace the massive losses.
By mid-November, after three months of urban fighting of an intensity unseen before, the Germans held most of the city. However, the Wehrmacht's achievements until then had been done at the cost of attracting more and more German troops at Stalingrad, while the flanks, which were defended by forces from the Axis countries, had become exposed to Soviet attacks.
Bundesarchiv, Bild 116-168-618 / [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/de/deed.en)], via Wikimedia Commons
RIA Novosti archive, image #602770 / Zelma / [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/deed.en)], via Wikimedia Commons
The shock was to come on November 19 when the Soviets launched Operation Uranus against the Romanian 3rd and 4th armies, which held the front line north and south of Stalingrad. The lack of a strong armored reserve to counter the Soviet tanks made inevitable the encirclement of the Axis forces at Stalingrad.
Hitler did not allow any attempt to retreat from Stalingrad, advocating the encircled forces to be supplied by airlift until they were to be relieved. The Germans launched Operation Wintergewitter accordingly, but the Luftwaffe proved to have nowhere near capacity to supply a force so large with food, ammunition, and fuel.
When on December 16, the Soviets began Operation Little Saturn, this time against the Italian 8th Army, the Germans had to stop attempting to make contact with the trapped forces. On January 13, the Soviets unleashed a new offensive with the result of destructing the Hungarian 2nd Army, which was occupying defensive positions along the Don River.
On the last day of January 1943, Friedrich Paulus - commander of the German 6th Army - surrendered, followed shortly by his soldiers yet alive, to Hitler's disappointment who had hoped that the newly field marshal should have committed suicide or fought to the last man.
The turning point represented by the Battle of Stalingrad, in addition to the irreplaceable losses for the Germans and their allies, signified the taking of strategic initiative by the Soviets who began to recapture the lost territory.