October 24, 1945 is the day that the United Nations officially came to being. On that day the UN charter was ratified by a majority of its signatories, including all permanent members of the UN Security Council. The treaty entered into force and the UN was officially born.
The story of that treaty, and of the San Francisco Conference that gave humanity the final draft of the United Nations Charter is super interesting, and expertly told by the writer Stephen Schlesinger, author of the book Act of Creation: The Founding of the United Nations.
I caught up with Schlesinger at the commemoration of the 70th Anniversary of the San Francisco conference and he tells some fun historical anecdotes about the drafting of the UN Charter. It even includes an awkward conversation between FDR and Winston Churchill, while the later was naked in a bathtub. Have a listen. And happy birthday, UN. May (an improved and more effective version of yourself) last another 70 years.