June-July 1946 The Manhattan Engineer District conducted Operation Crossroads, detonating two shots in the Bikini Atoll in the Marshall Islands. August 1, 1946 Atamic Energy Act signed by President Truman established the Atomic Energy Commission and transferred the Amny's Manhattan Engineer District atomic programs and facilities to the five member carmission. January 1, 1947 Atomic Energy Commission, officially began operation under Chaimman David E. March 12, 1947 President Truman proposed U. S. aid to Greece and Turkey, (the Truman Doctrine) . June 5, 1947 Plan for econamic aid to Europe proposed by Secretary of State George Marshall, later called the "Marshall Plan." April-May 1948 The Commission conducted Operation February 1948 A camminist coup in Czechoslovakia took June 23, 1948 . Berlin Blockade declared by the Soviet Union; lifted in May 1949, August 29, 1949 Sandstone, firing three shots on Enewetak in the Marshall Islands. control of the government. Soviet Union detonated its first atomic device. President Truman announced it on September 23. September 30, 1949 January 31, 1950 February 2, 1950 Communist Mao Tse-Tung establishec <he Peoples Republic of China. President Truman announced procram to develop the thermonuclear bomb. Klaus Fuchs, British atomic sclent:st, confessed to British investigators <nat he betrayed secrets of the atamic bar project to the Soviet Union. June 25, 1950 North Korean troops invaded South Korea, starting the Korean War.