It was the Manhattan Project that was initiated and tasked with developing the first nuclear weapon. A link can be found below, and a lot of information can be found by simply following it.
The atomic bomb was not invented by a project, it was invented by Leo Szilard in 1933.However the Manhattan Project built the first ones in 1945.
Manhattan project
The "Manhatton Project."
The first atomic bomb was built by scientists working on the Manhattan Project during World War II. This project was a top-secret research and development program undertaken by the United States, the United Kingdom, and Canada. The bomb was successfully tested in July 1945 before being used in combat against Japan in August 1945.
the first atomic bomb.....................
The Manhatten Project was the orginization that developed the atomic bomb.
Manhattan project
The project was called the Manhatten Project
the first atomic bomb.......................................
The military project to develop the US atomic bomb was the Manhattan Project. It included the first successful fission chain reaction in December, 1942, and culminated in the first atomic test explosion at Alamagordo, NM on July 16, 1945. Two bombs built under the project were dropped on the Japanese cities of Hiroshima and Nagasaki.
The test location of the first atomic bomb was located in California as it was known as the Manhattan Project.
the answer is "THE MANHATTAN PROJECT" :D