In June 1861, on what now is the National Mall in front of the Smithsonian’s National Air and Space Museum, Thaddeus Lowe demonstrated to President Lincoln how a gas-filled balloon might be used to spy on the enemy—thus helping the Union Army and establishing the earliest "air force."
The museum will commemorate the 150th anniversary of this event June 11, 2011, with an inflated balloon on the National Mall, and Kevin Knapp as Thaddeus Lowe.