The United Nations officially began on this day 66 years ago upon ratification of the United Nations Charter by the five permanent members of the Security Council (France, the Republic of China, the Soviet Union, the Unite Kingdom and the United States) and by a majority of the other 46 signatories. The Second World War in Europe had effectively ended with the German surrender in May 1945, but the War in Asia had continued until the Japanese surrender in August 1945; the United Nations was the new organisation intended to prevent future conflicts.
The United Nations has five principal organs: the General Assembly, the Security Council, the Economic and Social Council, the Secretariat and the International Court of Justice. The International Court of Justice is located in the Peace Palace in the Hague, Netherlands. The relatively recent International Criminal Court, which began operations in 2002, is also based in the Hague, but it is independent of the UN, being governed by the Rome Statute.
The United Nations was the successor to the League of Nations, the body set up after the First World War in an effort to prevent further conflict. The League of Nations was ultimately unsuccessful. The United Nations has been more enduring, but arguably that has been as the result of good luck rather than good management. Conflicting agendas of member nations have resulted in an organisation which is expensive to run and slow to act.