The Siege of Leningrad was a prolonged military blockade undertaken from the south by the Army Group North of Nazi Germany against the Russian city of Leningrad (today's St. Petersburg) on the Eastern Front in World War II.
The Finnish army invaded from the north, co-operating with the Germans until they had recaptured territory lost in the recent Winter War, but refused to make further approaches to the city.
The siege started on 8 September 1941, when the last road to the city was severed. Although the Soviet forces managed to open a narrow land corridor to the city on 18 January 1943, the siege was not lifted until 27 January 1944, 872 days after it began. It was one of the longest and most destructive sieges in history, and possibly the costliest in casualties suffered.