In Flat Broke in Paradise, Art Brown attends the San Francisco Conference, where the United Nations charter was developed. It was officially called the UN Conference on International Organization and was an attempt to do what the League of Nations, formed after World War I could not.
The 850 delegates and 2650 of their advisors and staff from over fifty nations descended on San Francisco in the spring of 1945. That doesn't take into account the 2500 representatives from the press. San Francisco was jumping with over eighty percent of the world population represented at the conference. The St. Francis Hotel housed delegations from 21 countries. The Mark Hopkins and Sir Francis Drake and other hotels housed the rest. It was a time of hope and bitter feelings. The conference nearly collapsed a number of times during heated debate. On June 26, 1945, the charter was signed and then ratified on the 24th of October of the same year.
Check out Steven Schlesinger's Act of Creation: The Founding of the United Nations for a fascinating behind-the-scenes look at the how the UN almost didn't happen.