The war fought between the Allies and Central Powers from 1914 to 1918 is known as World War I. It began after the assassination of Archduke Franz Ferdinand of Austria-Hungary and involved many of the world's great powers, divided into two main alliances: the Allies, which included France, the United Kingdom, Russia, and later the United States, and the Central Powers, primarily comprising Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria. The conflict had profound global implications, reshaping borders, leading to the establishment of new nations, and setting the stage for World War II due to unresolved tensions.