World War I began in 1914, after the assassination of Archduke Franz Ferdinand, and lasted until 1918. During the conflict, Germany, Austria-Hungary, Bulgaria and the Ottoman Empire (the Central Powers) fought against Great Britain, France, Russia, Italy, Romania, Japan and the United States (the Allied Powers).
World War 1 began on July 28, 1914. The conflict lasted four years, three months and 14 days, ending on November 11, 1918. The war began because of the assassination of Archduke Franz Ferdinand of Austria. He was heir to throne of Austria-Hungary and his death was the immediate cause of WW1.