The greatest siege in history begins as the German 6th Army and the Luftwaffe assault Stalingrad. 

Map 1: Fall Blau, Operation Blue. Note the positions of Voronezh, Stalingrad, the proximity of the great bends of the Don and Volga Rivers, and the Volga's route that leads from the Caspian Sea all the way to Moscow. 

Map 2: Stalingrad in 1942, showing the German advance

Places

The Children's Khorovod in front of Railway Station No. 1, after the air raids

People

Panzer General Friedrich Paulus, commander of the German 6th Army

Colonel-General Wolfram von RIchtofen, commander of the Luftflotte (air fleet) 4, 1942

Major-General Hans Hube, commander of the 16th Panzer Division

People's Commissar Nikita Khrushchev (left) and General Andrey Yeremenko (far right), commander of the South-Eastern Front (later renamed the Stalingrad Front), December 1942

General Vasily Chuikov (second from left), commander of the 62nd Red Army, December 1942

Sources

Antony Beevor, The Second World War. London: Little, Brown and Company, 2012.

William Craig, Enemy at the Gates: The Battle for Stalingrad. Old Saybrook, CT, USA: KOnecky & Konecky, 1973. 

Anthony Tucker-Jones, Slaughter on the Eastern Front: Hitler and Stalin's War 1941–1945. Stroud, Gloucestershire, UK: The History Press, 2017. 

Wikipedia: Battle of Stalingrad https://en.wikipedia.org/wiki/Battle_of_Stalingrad

—  Case Blue https://en.wikipedia.org/wiki/Case_Blue