The B-29 Superfortress bomber was the single most complicated and expensive weapon produced by the United States during World War II. Nearly 4,000 B-29s were built for combat in the Pacific theater, including the Enola Gay, the plane that dropped the first atomic bomb over Hiroshima. Assembled on a rush basis by a vast manufacturing program that involved hundreds of thousands of workers, the B-29 boosted the Allies' wartime fortunes as it transformed the economies of cities and towns from Seattle, Washington, to Marietta, Georgia, and from Wichita, Kansas, to Woodridge, New Jersey.