Hello! World War I was a global conflict that lasted from 1914 to 1918. It was fought between the Allied Powers, which included Britain, France, Russia, Italy, and the United States, and the Central Powers, which included Germany, Austria-Hungary, Bulgaria and the Ottoman Empire. The war began when a Serbian nationalist assassinated Archduke Franz Ferdinand of Austria-Hungary in 1914. This event triggered a series of alliances that eventually led to a full-scale war. The war saw unprecedented levels of destruction and loss of life due to new military technology such as machine guns and chemical weapons. It also saw the introduction of total warfare tactics such as unrestricted submarine warfare and strategic bombing campaigns. The war ended with an armistice in November 1918 with Germany signing an unconditional surrender. This conflict had far-reaching consequences for Europe and the world at large.