Fifteen thousand Seabees turned the island into the busiest airfield of the war, with six 2400 meters runways for attacks by United States Army Air Forces B-29 Superfortress bombers on enemy targets in the Philippines, the Ryukyu Islands, and mainland Japan, including the March 9/10 1945 Operation Meetinghouse firebombing of Tokyo and the atomic bombings of Hiroshima and Nagasaki.