The United Nations is an international organization founded in 1945.  It is currently made up of 193 Member States.  The mission and work of the United Nations are guided by the purposes and principles contained in the United Nations Charter and Statute of the International Court of Justice, signed in the San Francisco War Memorial Veterans Building on June 26, 1945.  Please see the UN's introduction to it's mandate and work, About the United Nations.  The United Nations YouTube Channel also features a series of informative clips about the work of the UN and is updated frequently.