On June 22, 1941, Hitler invaded the Soviet Union and German troops advanced towards Leningrad, Russia's second city with a population of three million. On June 27 the people of Leningrad began constructing fortifications around the city and steeled themselves for a defensive struggle which was to continue until January 1944. So fervent was the people's resistance that German forces, frustrated by their inability to take the stronghold, encircled...