Explore the timeline above to learn about the history of the Smithsonian National Air and Space Museum. The timeline includes images and stories featured in the new book Smithsonian National Air and Space Museum: An Autobiography, edited by Museum staff.

The millions of visitors who pass through the doors of the National Air and Space Museum in Washington, D.C. each year come to see the real thing, the actual aircraft and spacecraft that shaped history -- from the world's first airplane to the backup hardware for the latest robot spacecraft sent forth to explore another world. Few if any of those visitors realize that aerospace history was made here, on the very site of today's Museum on the National Mall, and 42 years before the first flight of an airplane. On June 16, 1861, the Columbia Armory stood where the museum is now located. Nearby was the Washington Gas Light Company. It was that useful combination -- available work space at the armory and the gas company next door -- that led Joseph Henry, then Secretary of the Smithsonian Institution, to instruct Thaddeus S. Lowe to inflate his balloon on the site. That flight was the first demonstration of aerial reconnaissance in American history, and it led directly to the establishment of a balloon corps for the Union armies, the nation's first military aviation unit.

This year the National Air and Space Museum celebrates its 35th anniversary. Share your memories with us.