World War One

World War One (1914-1918) began with the assassination of Archduke Franz Ferdinand of Austria-Hungary (June 28, 1914, Sarajevo, by Gavrilo Princip) and cascaded through a network of alliance commitments into the largest war the world had yet seen. The Western Front — the most iconic theater — consisted of 700 km of trenches from the Belgian coast to Switzerland, where millions died for yards of mud. The war introduced industrial-scale killing: poison gas (chlorine, phosgene, mustard gas), tanks, aircraft, artillery barrages (the Battle of the Somme began with a 7-day artillery barrage), and machine guns. The Battle of the Somme (July 1, 1916) produced 57,470 British casualties on its first day — the bloodiest day in British military history. The war killed 17 million people and redrew the world map: four empires (Ottoman, Austro-Hungarian, Russian, German) collapsed; the Treaty of Versailles created conditions that led directly to WWII.