When did the First World War begin?

The First World War, also called the Great War, began in the summer of 1914. Its immediate spark was the assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, in Sarajevo on 28 June 1914. A tangle of alliances then dragged the major European powers into war within weeks, with Austria-Hungary and Germany on one side and Russia, France, and Britain on the other. Fought largely from entrenched positions along the Western Front, the war introduced devastating new weapons such as machine guns, poison gas, tanks, and aircraft. It drew in nations from around the globe and cost around 20 million lives before ending with an armistice at 11 am on 11 November 1918. The peace terms that followed reshaped Europe and helped sow the seeds of a second global conflict.