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Albert Einstein sends a letter to Roosevelt
The letter describes the feasibility of atomic power, the potential use of atomic bombs and warns that Germany is already working on atomic research. -
American scientists conclude that plutonium can be used as a weapon.
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Attack on Pearl Harbor
Japanese forces attack the Unites States Naval base at Pearl Harbor, Hawaii, thus bringing the United States into World War Two. -
U.S. declares war on Japan.
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Harry S Truman, becomes the 33rd President
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The Target Committee meets for the first time
To decide which Japanese cities to target with the atomic bomb. -
Germany surrenders
Ends the war in Europe. US is still at war with Japan. -
Trinity Test
The Trinity test explosion of the world’s first atomic bomb occurred at Alamogordo, New Mexico. -
Potsdam Declaration
Called for the unconditional surrender of Japan, was issued by the United States, Britain, and China. While not specifying that the U.S. now had atomic weapons, the Declaration asserted that unless Japan surrendered, it would face "prompt and utter destruction.” The Japanese government chose to respond with silence. -
Hiroshima Bombed
A 15 kiloton atomic bomb nicknamed Little Boy over the Japanese city of Hiroshima. Approximately 130,000 people died in the explosion and the immediate after-effects of the attack. -
Nagasaki Bombed
A 21 kiloton atomic bomb named Fat Man was dropped on the Japanese city of Nagasaki. The original target was the city of Kokura. -
Japan's Emperor realizes he needs to surrender.
Japanese Emperor Hirohito decides that Japan must accept the Potsdam Declaration and surrender. -
Japan surrenders
In a recorded radio address, Emperor Hirohito announced to his people and to the world that Japan would surrender to the Allies.
