On this day, 80 years ago, on August 31, 1945 (July 24, 1945 in the lunar calendar), the U.S. military revealed the inside story of the creation of the atomic bomb. On August 31, 1945, the U.S. Department of War revealed that in order to produce atomic bombs, the United States had established three secret cities with a total population of 100,000. Thanks to good secrecy, workers never knew what they were making in the vast factory covering several square miles. They only know that a small amount of stuff is extracted from a large amount of uranium ore. The US$2 billion scientific research project is headed by Major General Leslie Grove. The scientists who designed the atomic bomb and studied applications for atomic fission live in Los Alamos, a city founded on a highland 30 miles north of Santa Fe, New Mexico. Robert Oppenheimer, a physicist from the University of California, led this arduous scientific effort. Oak Ridge, Tennessee, gradually developed into a city of 75,000 people. The "Manhattan Engineering District" is here and the main production equipment is also here. Other atomic power plants were built in Hanford, Washington. Some production equipment can use atomic energy to serve civil construction.