Original: Included in the permanent collections are one of four surviving Convair B-36s,  the only surviving XB-70 Valkyrie, and Bockscar—the B-29 Superfortress that dropped an atomic bomb on Nagasaki during World War II.
Simplified: The museum has many rare and important aircraft and other exhibits, including one of four surviving Convair B-36s,  the only surviving XB-70 Valkyrie, and Bockscar—the B-29 Superfortress that dropped the second atomic bomb in World War II.