After securing Saipan, the population center of the Marianas, on July 7, 1944, the attention of the United States Armed Forces turned south to nearby Tinian, which had been selected by war planners in the Pacific theatre as the most favorable site to launch bombing raids against the Japanese mainland, about 1,200 miles (2,000 km) to the North. In the heavy bombardment preceeding invasion on July 24, Tinian earned the distinction of being the first target of a napalm bomb. A successful feint for the major settlement of Tinian Town diverted defenders from the actual landing site on the north of the Island. By the time the island was secured on July 31, the entire garrison of over 8,000 Japanese defenders was lost.
At this point 15,000 SeaBees began work to transform the island into the busiest airfield of the war, with six 8,000 foot (2400 m) runways for B-29 raids against the Japanese mainland. It was from Tinian that the bombers carrying the atomic bombs Little Boy and Fat Man were launched against Hiroshima and Nagasaki. The airfields now lay overgrown and abandoned.