Nuclear Plants

It was really in 1942, when construction really begun. Scientists believed they had enough knowledge and theory, and what they really needed was the resources so they could put their theory into practice.
The largest step in order for the project to go underway was when the U.S. ordered 1250 pounds of Uranium and 52000 acres to be purchased in Oak Ridge, Tennessee. This was to be the first of many major factories and laboratories used for project X.

By 1945 Oak ridge had 75,000 residents

The rural farm area home to less than a thousand was transformed into massive town with one purpose that less than 95% of the residents knew about, to manufacture nuclear weapons.
Oak ridge is just one of about 30 laboratories/factories used in the Manhattan Project which were located mainly in the United States but also Canada and Britain. The other key factory was Los Alamos as seen on the map above.
Its also estimated that 90% of the money spent was for building plants and other materials. This would equivalent to about 27 billion U.S. dollars.