the Pearl Harbor attack in 1942, 26 countries determined not to
repeat the same mistakes of World War I, signed a Declaration
by United Nations in Washington D.C. Each country pledged to fight
the Axis and not to make any separate peace agreements. FDR, in
his many fire-side chats kept referring to these friendly countries
as the United Nations.
April 25, 1945, a conference of 50 countries met in San Francisco
and prepared a charter for the United Nations. The U.N. was
officially born on October 24 1945.