The conflict known as the "War to End All Wars" refers to World War I, which lasted from 1914 to 1918. The term was popularized in the aftermath of the war, reflecting the widespread hope that the devastation and losses experienced during this global conflict would lead to lasting peace. World War I was notable for its unprecedented scale, encompassing numerous nations and utilizing modern warfare technology. However, the harsh realities of the post-war treaties and the unresolved issues it left behind contributed to the emergence of World War II, undermining the initial optimism associated with the title "the war to end all wars."