The Great War, also known as World War 1, was one of the deadliest and most significant conflicts in modern history. It lasted from 1914 to 1918, and involved many of the world's major powers. Synonyms for The Great War include the First World War, the War to End All Wars, and the European War. The term "World War 1" was not widely used until after World War 2, when it became necessary to distinguish between the two conflicts. Other colloquial expressions for the war include the Great War for Civilization and, for a time during the early years of the conflict, simply "the war".