Los Alamos
The secret New Mexico mesa where Oppenheimer and the Manhattan Project designed and built the first atomic bombs, a city that officially did not exist.
The town where the atomic bomb was built did not officially exist. For two years its thousands of residents shared a single mailing address, Post Office Box 1663, Santa Fe, New Mexico. Babies born there had that box number entered as their birthplace. Behind the barbed wire sat the most concentrated collection of scientific talent ever assembled, sent to a remote mesa to answer one question: could a bomb be built before Germany built one first.
The Hill
In late 1942 J. Robert Oppenheimer and General Leslie Groves chose a boys' ranch school on the Pajarito Plateau, 7,300 feet up in northern New Mexico, precisely because it was hard to reach and easy to seal. The Army seized the property, closed the school, and by early 1943 physicists were arriving at a site marked on no map. They called it Project Y, or simply the Hill. Oppenheimer had argued for gathering the scientists in one place so they could talk freely; Groves wanted them fenced in so they could not talk at all. The compromise was a walled town where the work was open on the inside and invisible from the outside.
Life there was improvised and strange. Nobel laureates queued for water that ran brown. Nobody could tell a spouse what they did all day. The population climbed from a few hundred to more than 8,000 by war's end, a government boomtown of muddy roads, poker games, and a birth rate so high that Groves complained about it in writing.
The gadget and after
The laboratory's job was to turn the physics of fission into deliverable weapons. It produced two designs: a simple uranium gun-type bomb the team was confident enough to use untested, and a far trickier plutonium implosion device that had to be proven first. On July 16, 1945, in the desert near Alamogordo, Los Alamos detonated that implosion design in the Trinity test, the first nuclear explosion in history. Oppenheimer later said the flash brought to mind a line from Hindu scripture: 'Now I am become Death, the destroyer of worlds.' Three weeks later the two bombs fell on Hiroshima and Nagasaki.
Secrecy, it turned out, leaked. At least two insiders, the physicist Klaus Fuchs and the machinist David Greenglass, were passing the implosion design to the Soviet Union while they worked on it. When Moscow tested a near-copy of the Nagasaki bomb in 1949, years ahead of American estimates, part of the blueprint had come straight off the Hill.
Permanence
Los Alamos was supposed to be temporary, a wartime crash program that would disband once the bomb was built. It never did. It became Los Alamos National Laboratory, a permanent pillar of the American nuclear complex that today designs warheads and models weapons that can no longer be legally tested, employing more people than the wartime town ever held. The secret city that did not exist is now a fixture, still perched on its mesa, still building the weapons it was invented for. The mailing address has changed. The mission never did.