Episode five tells how, after 1916 and the hell of the Somme and Verdun, the imperial powers redoubled their efforts to crush their enemies. In Germany the new commander in chief, Paul von Hindenburg, and his deputy, Erich Ludendorff, demanded that German industry doubled its output of shells, to 11 million a month, and treble production of machine guns, artillery and aircraft. To meet these new targets Germany needed three-million more workers. Those who were too young or too old to fight had to work in the munitions factories. More than a million PoWs would be put to work, hundreds of thousands of inhabitants of occupied Belgium, France and Russia would become forced labourers. Sixty-five thousand of these men would be used to build a massive new line of fortifications along the Western Front, the Hindenburg Line. The Hindenburg Line was built in almost total secrecy. The Allies were stunned. On the Eastern Front the Russian army was also in disarray, and the Tsar was forced to abdicate. The Germans provided a special train to carry the Communist revolutionary Vladimir Ilyich Lenin from exile in Switzerland back to Russia. The country was on the verge of collapse.