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Events > Dawn of the Atomic Era, 1945

The atomic bombings of Hiroshima and Nagasaki and the surrender of Japan were the last acts of the Second World War.  The most destructive weapon in the history of combat had helped bring an end to the most destructive conflict in human history.  

A Frenchman weeps as he watches German troops march into Paris, June 14, 1940.The Manhattan Project and the devastation that its successful outcome wrought are inexplicable outside the context of the Second World War.  The project began as a race to acquire the bomb before Nazi Germany did, and the prospects of an atomic bomb in the hands of one of the world's most oppressive and murderous regimes were chilling indeed.  In a war initiated by German aggression and dreams of conquest, tens of millions died.  Few European nations escaped grievous injury, but nowhere was the suffering worse than in Poland, where six million or more lost their lives, and in the Soviet Union, where more than 25 million may have died.  Other Allies suffered terribly as well, including about 600,000 deaths in France and 400,000 dead Britons (including many in the Pacific Theater).  Approximately six million Jews of all nations died during the Holocaust.  Even small and too often forgotten nations suffered horribly.  In Yugoslavia, for example, as many as two million people may have died during the war.  Germany itself lost over four million.  The stakes in the race for the bomb were thus very high.  Tens of million more might have died -- and Western civilization itself might have been eclipsed -- if Germany had proven the victor.

The loss of life in the Pacific war was equally horrific.  Victims of Japanese aggression suffered terribly, from Korea to the Philippines to Southeast Asia to the islands of the Pacific.  The nation hardest hit, however, was probably China.  Beginning with the invasion by Japan in 1931, perhaps 15 million Chinese died at the hands of the Japanese Army or from the war's attendant starvation and disease.  The toll on Asia and the Pacific was psychological as well as physical; controversy still rages over the numerous war crimes committed by the Japanese Army, including biological warfare experiments conducted on civilians, the execution of prisoners of war, and wholesale rape and murder committed against entire cities, such as happened in 1937 in the Chinese city of Nanking where 200,000 or more Chinese civilians may have died.  Well over two million Japanese soldiers and civilians lost their lives during the war, of which perhaps as many as 300,000, or even more, were as a result of the two atomic bombings.  About 300,000 Americans died during the wars against Germany and Japan.  Though no one will ever know for certain, the worldwide death toll for the war from 1931 to 1945 probably reached 60 million.

Manhattan Project facilitiesThe atomic bomb was the scientific and technological exclamation point at the end of this worst-of-all wars that was won by technologically-advanced industrial might.  That the bomb was completed by the United States in time to help finish the conflict is remarkable.  Most of the theoretical breakthroughs in nuclear physics that made it possible dated back less than twenty-five years, and, with new findings occurring faster than they could be absorbed by practitioners in the field, many fundamental concepts in nuclear physics and chemistry had yet to be confirmed by laboratory experimentation.  Nor was there any conception initially of the design and engineering difficulties that would be involved in translating what was known theoretically into working devices capable of releasing the enormous energy of the atomic nucleus in a predictable fashion.  The industrial base created in a handful of years to transform these theories into reality was, by 1945, comparable in size to the American automobile industry.  Approximately 130,000 people were employed by the project at its peak, from laborers to Nobel Prize winners.  The Manhattan Project was as much a triumph of engineering and industry as of science.

Excerpt from the comic book "Adventures Inside the Atom." Click on this image or visit the "Library" to view the whole comic book.Without the leadership of Leslie Groves and Robert Oppenheimer, as well as that of Crawford Greenewalt of DuPont and other contractors, the revolutionary breakthroughs in nuclear science achieved by Enrico Fermi, Niels Bohr, Ernest Lawrence, and their colleagues would not have produced the atomic bomb during World War II.  Despite numerous obstacles, the United States was able to combine the forces of science, government, academia, the military, and industry into an organization that took nuclear physics from the laboratory and on to the battlefield with a weapon of awesome destructive capability, making clear the importance of basic scientific research to national defense.  The Manhattan Project became the organizational model behind the remarkable achievements of American "big science" during the second half of the twentieth century.  When President John F. Kennedy announced his goal of putting a man on the moon by the end of the 1960s, it was the Manhattan Project that he invoked for its spirit of commitment and patriotism.

To view the next "event" of the Manhattan Project, proceed to "1945-present: Postscript -- The Nuclear Age."


Sources and notes for this page.

Portions of the text for this page were adapted from, and portions were taken directly from Office of History and Heritage Resources publications: F. G. Gosling, The Manhattan Project: Making the Atomic Bomb (DOE/MA-0001; Washington: History Division, Department of Energy, January 1999), 54, and The Signature Facilities of the Manhattan Project (Washington: History Division, Department of Energy, 2001), 1.  The estimates of deaths from the war are from Gerhard L. Weinberg, A World at Arms: A Global History of World War II (New York: Cambridge University Press, 1994), 322 and 894-895, and Chapter 1, "Rubble: The World in 1945," in Thomas G. Paterson, On Every Front: The Making and Unmaking of the Cold War, Revised Edition (New York: W. W. Norton and Company, 1992), 3-20.  The photograph of the post-war celebration is courtesy the Oak Ridge National Laboratory.  The photograph of the Frenchman watching German troops enter Paris, and of the baby in Shanghai, 1937, are both courtesy the National Archives.  The map of the MED facilities in North America is reproduced from Vincent C. Jones, Manhattan: The Army and the Atomic Bomb, United States Army in World War II (Washington: Center of Military History, United States Army, 1988), 63.  Click here for more information on the comic book image.

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