Great Battles of WWII: Stalingrad

Stalingrad features two campaigns based around the events in southern Russia between summer 1942 and early 1943. The Wehrmacht campaign has the player commanding the 6th Army as it approached the city and the battles for the city itself. The RKKA (Workers' and Peasants' Red Army) campaign follows the Red Army's progress as it liberated Stalingrad and destroyed the 6th Army. In total there are 36 missions, including 7 "bonus" missions that are unlocked if the player fulfills certain objectives in preceding maps. The maps themselves are reproduced from historical tactical maps and actual aerial photography taken during the period that the campaign covers.

Source: Wikipedia, "Stalingrad (2005 video game)", available under the CC-BY-SA License.