The United Nations is an international organization founded in 1945 after the Second World War by 51 countries to maintain peace and security, ensure human rights, and promote a better standard of living for all.
After World War II, President Franklin D. Roosevelt and British Prime Minister Winston Churchill were the main signatories of the declaration that vowed to create an international postwar peacekeeping organization. Other works of the U.N. are to protect human rights and deliver humanitarian aid.
The complex has served as the official headquarters of the United Nations since its completion in 1951. The United Nations complex itself was designed by lead architect Wallace Harrison.
The headquarters hold the International General Assembly and the Security Council meetings. The U.N.'s three regional headquarters are in Geneva, Switzerland, Vienna, Austria, and Nairobi, Kenya.
Even though the U.N. is housed in New York City, the land and buildings are under the administration of the U.N. and not the U.S. government.