Biography: Groves oversaw the construction of the Pentagon, the famous headquarters of the United States Department of Defense, and most crucially he oversaw the Manhattan Project during World War II. This top secret role led to the development and eventual use of nuclear weapons.
After serving time with the US Army Corps of Engineers in places such as Nicaragua, where he assisted the city of Managua after a devastating 1931 earthquake, and developing the Pentagon building, he was selected to oversee the Manhattan Project in 1942. Groves was involved in virtually every stage of the bomb's development, selecting test and laboratory sites, and working closely with figures such as Robert J. Oppenheimer, who ran the Los Alamos research center.
Groves also helped select cities in Japan that the atomic bomb would eventually be used on - Hiroshima and Nagasaki. After the war, he ran the military aspect of nuclear weapons as production of weapons was moved to civilian control. On January 30, 1948, He was admonished by Army Chief of Staff Dwight D. Eisenhower for his rudeness, promotion maneuvering, arrogance and contempt for rules, and Eisenhower made it clear Groves would not be promoted to Chief of Engineers. He resigned from the Army a month later.
- 1941-09-11 Construction of the Pentagon begins in Arlington County, Virginia (completed Jan 15, 1943). Designed by architect George Bergstrom and built by contractor John McShain, construction was overseen by Leslie Groves.
- 1942-08-13 The 'Manhattan Project' commences, under the direction of US General Leslie Groves: its aim - to deliver an atomic bomb