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The '''Manhattan Project''' was the code word for the project that developed the first nuclear weapons&mdash;"atomic bombs" as they were then called&mdash;in history. The formal code name was "Manhattan Engineering District," named after the Manhattan Engineer District of the [[United States Army Corps of Engineers]].  Manhattan borough had at least 10 sites that supported the project, including the project's first headquarters located in a skyscraper across from City Hall.<ref>Robert S. Norris, "The Manhattan Project" (Black Dog & Leventhal). The book claims that spies stole some of the project's top secrets from Manhattan.</ref>

The '''Manhattan Project''' was a 6-year effort to develop a nuclear fission weapon before the Nazis could, sparked by a warning from European scientists to US President Roosevelt.

 

 

The term ''Manhattan Project'' was the code word for the project that developed the first nuclear weapons - "atomic bombs" as they were then called - in history. The formal code name was "Manhattan Engineering District," named after the Manhattan Engineer District of the [[United States Army Corps of Engineers]].  Manhattan borough had at least 10 sites that supported the project, including the project's first headquarters located in a skyscraper across from City Hall.<ref>Robert S. Norris, "The Manhattan Project" (Black Dog & Leventhal). The book claims that spies stole some of the project's top secrets from Manhattan.</ref>

It had been known since about 1900 that the natural decay of radioactive elements produced quantities of energy that were enormous compared to those produced by chemical reactions. The problem was that natural processes liberated it very slowly; for example, the half-life of radium is 1602 years, so a lump of radium will stay warm for thousands of years, but is not warm enough to be a useful source of energy. In 1914, [[H.G. Wells]] wrote a science-fiction novel, [[The World Set Free]], describing "atomic bombs," in which the release of energy had been artificially speeded up; his description of the process was, however, imaginary gobbledegook. In 1933, Hungarian-born physicist [[Leo Szilard]] invented the idea of the nuclear ''chain reaction'' which made the rapid release of atomic energy a theoretical possibility. The idea was in the air, and in fact during the Second World War, Japan, Germany, USSR, and the United States all worked on atomic bomb projects, although the Japanese and German projects did not get far.

It had been known since about 1900 that the natural decay of radioactive elements produced quantities of energy that were enormous compared to those produced by chemical reactions. The problem was that natural processes liberated it very slowly; for example, the half-life of radium is 1602 years, so a lump of radium will stay warm for thousands of years, but is not warm enough to be a useful source of energy. In 1914, [[H.G. Wells]] wrote a science-fiction novel, [[The World Set Free]], describing "atomic bombs," in which the release of energy had been artificially speeded up; his description of the process was, however, imaginary gobbledegook. In 1933, Hungarian-born physicist [[Leo Szilard]] invented the idea of the nuclear ''chain reaction'' which made the rapid release of atomic energy a theoretical possibility. The idea was in the air, and in fact during the Second World War, Japan, Germany, USSR, and the United States all worked on atomic bomb projects, although the Japanese and German projects did not get far.