United Nations (UN), international organization established on October 24, 1945. The United Nations (UN) was the second multipurpose international organization established in the 20th century that was worldwide in scope and membership. Its predecessor, the League of Nations, was created by the Treaty of Versailles in 1919 and disbanded in 1946. Headquartered in New York City, the UN also has regional offices in Geneva, Vienna, and Nairobi. Its official languages are Arabic, Chinese, English, French, Russian, and Spanish. For a list of UN member countries and secretaries-general, see below.