Battle of Stalingrad (1942): Pocket closed

Street fighting in the ruins, the factory district, and Mamayev Kurgan produced casualty totals in a band of about 1.7-2 million killed, wounded and captured on both sides -- among the costliest single battles ever recorded. The Soviet encirclement (Operation Uranus, 19 November 1942) trapped the 6th Army when the Romanian and Italian flanks collapsed.

Relief (Winter Storm) failed. The airlift could not supply a pocket. The surrender of a German field army on the Volga ended the myth of unbroken Wehrmacht success in the east and became the Soviet -- and later Russian -- patriotic hinge, taught in English as the Eastern Front's turning point beside Midway and El Alamein.

Stalingrad was a street war that became an encirclement, then a starvation, then a surrender -- and a memory industry on a hill. Case Blue (1942) aimed at oil and the Caucasus. The city on the river was a transport hinge and a name. Hitler and Stalin both refused to treat it as optional.