World War I or the First World War, (28 July 1914 – 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. It was fought between two coalitions, the Allies (primarily France, the United Kingdom, Russia, Italy, Japan and the United States) and the Central Powers (led by Germany, Austria-Hungary, and the Ottoman Empire). Fighting occurred throughout Europe, the Middle East, Africa, the Pacific, and parts of Asia. An estimated 9 million soldiers were killed in combat, plus another 23 million wounded, while 5 million civilians died as a result of military action, hunger, and disease. Millions more died as a result of genocide, while the 1918 Spanish flu pandemic was exacerbated by the movement of combatants during the war. The first decade of the 20th century saw increasing diplomatic tension between the European great powers. This reached breaking point on 28 June 1914, when a Bosnian Serb named Gavrilo Princip assassinated Archduke Franz Ferdinand, heir to the Austro-Hungarian throne. Austria-Hungary held Serbia responsible, and declared war on 28 July...