Wendover Air Force Base is a former United States Air Force base in Utah now known as Wendover Airport. During World War II it was a training base for B-17 and B-24 bomber crews. It was the training site of the 509th Composite Group, the B-29 unit that dropped the Hiroshima and Nagasaki atomic bombs. In 2009, a hangar at the base dubbed The Manhattan Project's Enola Gay Hangar was listed as one of the most endangered historic sites in the U.S.