The situation
In summer 1942 Germany drove toward the Caucasus oil fields, with the Sixth Army sent to take Stalingrad and protect the flank. The city also carried Stalin's name, which raised the stakes for both dictators.
The decision
The Germans took most of the city but never cleared the last Soviet positions along the river. While the fighting ground on, the Soviets built up reserves. On 19 November 1942 Operation Uranus struck the weaker Romanian armies on the flanks, and within days the Sixth Army was surrounded.
Hitler forbade a breakout and relied on a promised airlift that never came close to meeting the army's needs. A relief attempt in December failed.
What it cost
The battle is among the deadliest in history, with combined military and civilian casualties commonly estimated at well over a million. Paulus surrendered on 31 January 1943 and the last German forces two days later. Of roughly 91,000 prisoners taken, only about 5,000 ever returned home.