October 24, 1945—the day The United Nations officially came into existence. Three years later, it began to be celebrated as United Nations Day. The original founding members include the United States of America, the United Kingdom of Great Britain and Northern Ireland, the Union of Soviet Socialist Republics, China, Australia, Belgium, Canada, Costa Rica, Cuba, Czechoslovakia, Dominican Republic, El Salvador, Greece, Guatemala, Haiti, Honduras, India, Luxembourg, Netherlands, New Zealand, Nicaragua, Norway, Panama, Poland, Union of South Africa, and Yugoslavia. Succeeding members include Bolivia, Brazil, Chile, Columbia, Ecuador, Egypt, Ethiopia, France, Iran, Iraq, Lebanon, Liberia, Mexico, Paraguay, the Philippines, Peru, Saudi Arabia, Syria, Turkey, Uruguay, and Venezuela.
To know more about the United Nations, visit http://www.un.org/en/sections/history/history-united-nations/