Answer: It was assumed World War I would be the last war.
World War I (also WWI, WW1, the First World War or the Great War) was a conflict that started in Europe and lasted from July 1914 to November 1918. The high number of losses is attributed to the development of new weapons and tactics, the stalemate of trench warfare and the pandemics that followed. It was one of the deadliest conflicts in history.
WWI was described as "the war to end all wars" by contemporaries. They believed that the political rearrangement of Europe would be enough to stop any other conflict from arising. Efforts were taken to ensure this as well, such as the League of Nations, and the extreme sanctions imposed on Germany. Ironically, these may have contributed to the rise of the Nazi Party and WWII.
