The World War was a military conflict centered on Europe that began in the summer of 1914. The fighting ended in early 1918 in eastern Europe and by 1920 in eastern Europe. This conflict involved most of the world's great powers, assembled in two opposing alliances: The Allies (centred around the Triple Entente) and the Central Powers. More than 70 million military personnel, including 60 million Europeans, were mobilized in one of the largest wars in history. More than 15 million people were killed, making it also one of the deadliest conflicts in history. The war is also known as the Great War and the War to End All Wars.