Give the detailed information about the UNO before its foundation?

1)       The onset of Second World War brought about the end of League of Nations founded after First World War.
2)       However, the disastrous impact of Second World War convinced all the countries about the need for such organization.
3)       In 1941, American President Franklin Roosevelt and British Prime Minister Winston Churchill announced Atlantic Charter.
4)       The main objective of this charter was to finalize the details about the foundation of an international organization for establishment of world peace.
5)       In next year's, the allied nations held meetings at Washington, Quebec, Tehran, Yalta to plan the formation of the organization.
6)       Finally, on April 1945, at San Francisco, 57 countries approved the plan of the organization.
Accordingly, on 24th October 1945, UNO came to be established in New York