1940s By groovydana Period: Jan 1, 1940 to Dec 31, 1949 1940s Apr 9, 1940 Hitler invades Norway and Denmark Dec 7, 1941 Japan bombed Pearl Harbor Apr 12, 1945 President FD Roosevelt dies FDR has a brain hemorrhage and Harry S. Truman succeeds him as president. Aug 6, 1945 US drops the atomic bomb on Hiroshima, Japan Aug 9, 1945 US drops 2nd atomic bomb on Nagasaki, Japan Aug 14, 1945 Japan surrenders Mar 15, 1947 Truman Doctrine US granted $400 million in aide to Greece and Turkey to fight communism.