The siege of Leningrad was a prolonged military blockade undertaken from the south by the Army Group North of Nazi Germany against the Soviet city of Leningrad on the Eastern Front in World War II. The Finnish army invaded from the north, co-operating with the Germans until Finland had recaptured territory lost in the recent Winter War, but refused to make further approaches to the city. Also co-operating with the Germans after August 1942 was the Spanish Blue Division. It was transferred to the southeastern flank of the siege of Leningrad, just south of the Neva near Pushkin, Kolpino and its main intervention was in Krasny Bor in the Izhora River area.
The siege began on 8 September 1941, when the Wehrmacht severed the last road to the city. Although Soviet forces managed to open a narrow land corridor to the city on 18 January 1943, the Red Army did not lift the siege until 27 January 1944, 872 days after it began. The blockade became one of the longest and most destructive sieges in history, and it was possibly the costliest siege in history due to the number of casualties which were suffered throughout its duration.