[narrator] As the Nazi forces advanced

[narrator] As the Nazi forces advanced, Leningrad's terrified civilians raced to build trenches and anti-tank fortifications. [tense music] The Nazis were advancing at speed, and the Russian Red Army and volunteer forces could not build their defences quickly enough. The city was almost completely encircled by the Germans with their Finnish allies to the north. By the 8th of September, the only way in or out of Leningrad was by water, via the vast Lake Ladoga. [news commentator] The camera can show but little of the suffering and death and horror that has reigned upon this heroic city in the long months during which the Nazis have vainly smashed at Leningrad's gates. [narrator] Eventually, though, the frantic trench building by Leningrad's inhabitants paid off. [man shouting]