Fifty nations gathered in San Francisco from April 25th, 1945 to June 26th, 1945 to negotiate the details on the establishment of the United Nations. The basic outlines of the new organization had already been agreed to both Dumbarton Oaks Conference and at Yalta.
The delegates reviewed the agreements reached at Dumbarton Oaks. They agreed to add the concept of regional organizations under the umbrella of United Nations.
The one major disagreement at the conference was the veto power that was given to the big five. Most of the other countries opposed the provision and wanted to at least decrease its scope. However, the major powers refused to cede and the veto remained. President Roosevelt who had been the key mover behind the creation of the United Nations had died before the conference had opened in his memory the attendees traveled to nearby Muir National Forest and placed a plaque in his memory.
On June 25th, 1945 the conference met for the last time to approve the new charter. It was approved unanimously by the delegates.