Divided Europe -- A fatal shot -- War in the west -- Fighting men -- Joining up -- Stalemate -- Life in the trenches -- Ready to fight -- Lines of communication -- Keeping watch -- Bombardment -- Over the top -- Wounded -- Women at war -- War in the air -- Zeppelin -- War at sea -- Gallipoli -- Verdun -- Gas attack -- In the east -- War in the desert -- Espionage -- Tank warfare -- The US joins in -- Mines and mud -- The final year -- Armistice and peace -- The cost of war -- Did you know? -- People and places -- Find out more.