The son of a U.S. Army chaplain , Groves lived at various Army posts during his childhood . In 1918 , he graduated fourth in his class at the U.S. Military Academy at West Point and was commissioned into the U.S. Army Corps of Engineers . In 1929 , he went to Nicaragua as part of an expedition to conduct a survey for the Inter-Oceanic Nicaragua Canal . Following the 1931 earthquake , Groves took over Managua 's water supply system , for which he was awarded the Nicaraguan Presidential Medal of Merit . He attended the Command and General Staff School at Fort Leavenworth , Kansas , in 1935 and 1936 ; and the Army War College in 1938 and 1939 , after which he was posted to the War Department General Staff . Groves developed " a reputation as a doer , a driver , and a stickler for duty " and in 1940 he became special assistant for construction to the Quartermaster General , tasked with inspecting construction sites and checking on their progress . In August 1941 , he was appointed to create the gigantic office complex for the War Department 's 40,000 staff that would ultimately become the Pentagon
1931 earthquake
1931 Nicaragua earthquake
Leslie Groves