Leonardo da Vinci's early notes and sketches of human flight some 400 years before the airplane's invention are making a rare visit to the Smithsonian's National Air and Space Museum in Washington.
Beginning Friday, the museum will display da Vinci's ``Codex on the Flight of Birds'' through Oct. 22. The notebook dates to between 1505 and 1506 when the famous Renaissance artist also painted his "Mona Lisa'' masterpiece.
Da Vinci studied birds to describe how humans could one day fly. The historic document is being shown near Orville and Wilbur Wright's 1903 Flyer, the world's first successful powered aircraft. Interactive stations allow visitors to flip through the codex pages.
The Biblioteca Reale in Turin, Italy, is loaning the document to the Smithsonian. It's been shown in the U.S. once before.