The Siege of Leningrad was a military blockade undertaken by the Axis powers against the city of Leningrad in the Soviet Union on the Eastern Front of World War II from 1941 to 1944. Leningrad, the country's second largest city, was besieged by Germany and Finland for 872 days, but never captured. The siege was the most destructive in history and possibly the most deadly, causing an estimated 1.5 million deaths, from a prewar population of 3.2 million. It was not classified as a war crime at the time, but since then, some historians have classified it as a genocide due to the intentional destruction of the city and the systematic starvation of its civilian population.