The "Bicentennial Era" was a series of observances, celebrations, and commemorations leading up to the 200th anniversary of the adoption of the Declaration of Independence on Sunday, July 4, 1976. The Smithsonian celebrated the 200th Fourth of July with a twelve-week Bicentennial Festival of American Folklife, a visit from Queen Elizabeth II, and the opening of the National Air and Space Museum on the National Mall on July 1, 1976.