Leslie Groves died August 17, 1896.
Leslie Groves . Following the 1931 Nicaragua earthquake , Groves took over responsibility for Managua 's water supply system , for which he was awarded the Nicaraguan Presidential Medal of Merit . In August 1941 , he was given responsibility for the gigantic office complex to house the War Department 's 40,000 staff which would ultimately become the Pentagon . In September 1942 , Groves took charge of the Manhattan Project . After the war , Groves remained in charge of the Manhattan Project until responsibility for nuclear weapons production was handed over to the United States Atomic Energy Commission in 1947 .