On what date did the United Nations officially come into existence?

The United Nations officially came into existence on 24 October 1945.

The date marks the entry into force of the United Nations Charter, the organisation’s founding treaty. The Charter had been signed in San Francisco on 26 June 1945 by representatives of 50 countries. Poland signed later and became the 51st original member because it had not been represented at the conference.

The United Nations replaced the League of Nations, which had been created after the First World War but could not prevent the Second World War. Its founding purpose was to help maintain international peace, develop friendly relations among countries, and support cooperation on global problems.

United Nations Day is observed every year on 24 October. The organisation’s headquarters are in New York City, although its system includes major offices in Geneva, Vienna, and Nairobi. The UN’s membership has since grown from 51 original members to 193 member states.