World War I or the First World War, often abbreviated as WWI or WW1, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously known as the Great War or "the war to end all wars",[7] 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.[8][9] It also was one of the deadliest conflicts in history,[10] with an estimated 8.5 million combatant deaths and 13 million civilian deaths as a direct result of the war,[11] while resulting genocides and the related 1918 Spanish flu pandemic caused another 17–100 million deaths worldwide,[12][13] including an estimated 2.64 million Spanish flu deaths in Europe and as many as 675,000 Spanish flu deaths in the United States.[14]