WWII and Early Cold War Timeline By Zyhro Dec 7, 1941 Japanese Attack on Pearl Harbor On December 7th, 1941, Japan attacked the American Navy base in Hawaii. 2,403 people were killed with 1,178 others being wounded. This cause the U.S to declare war on Japan and join WWII. Jun 6, 1944 D-Day Oct 24, 1945 Creation of the United Nations Mar 12, 1947 Truman Doctrine Apr 4, 1949 NATO Created Aug 29, 1949 Soviet Union Obtains Nuclear Weapons Period: Jun 25, 1950 to Jul 27, 1953 Korean War May 14, 1955 Warsaw Pact Created Period: Oct 29, 1956 to Nov 7, 1956 Suez Crisis Aug 13, 1961 Construction of Berlin Wall Begins