The war on the Eastern Front was racial - Slav verses Teuton. It was highly mobile, fought across brutal terrain from the Urals to the Alps. It initiated many horrors of 20th-century warfare - chemical weapons, mass expulsions of civilians, the persecution of Jews. The Italian front with Austro-Hungary was perhaps the bitterest of all. Soldiers lived and fought for years in the harshest environments, enduring avalanches and frostbite as well as relentless enemy action. Mistrust and contempt increasingly threatened alliances. Germany shored up her ally Austria-Hungary, feeling herself 'shackled to a corpse', while Austria-Hungary saw Germany as her 'secret enemy'. Show less