World War I World War I (often abbreviated as WWI or WW1), also known as the First World War, the Great War, the Seminal Catastrophe, and initially in North America as the European War, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously described as "the war to end all wars", it led to the mobilisation of more than 70 million military personnel, including 60 million Europeans, making it one of the largest wars in history. It is also one of the deadliest conflicts in history, with an estimated nine million combatants and seven million civilian deaths as a direct result of the war, while resulting genocides and the resulting 1918 influenza pandemic caused another 50 to 100 million deaths worldwide. On 28 June 1914, Gavrilo Princip, a Bosnian Serb Yugoslav nationalist, assassinated the Austro-Hungarian heir Archduke Franz Ferdinand in Sarajevo, leading to the July Crisis. In response, on 23 July Austria-Hungary issued an ultimatum to Serbia. Serbia's reply failed to satisfy the Austrians, and the two moved to a war footing. A network of interlocking alliances enlarged the crisis from a bilateral issue in the Balkans to one involving most of Europe. By July 1914, the great powers of Europe were divided into two coalitions: the Triple Entente—consisting of France, Russia, and Britain—and the Triple Alliance of Germany, Austria- Hungary, and Italy (the Triple Alliance was only defensive in nature, allowing Italy to stay out of the war until April 1915, when it joined the Allied Powers after its relations with Austria-Hungary deteriorated).
- Fall '18