A 500-year-old notebook written in by Leonardo da Vinci has gone on display at a museum in Washington.
The “Codex on the Flight of Birds” details da Vinci’s thoughts on how humans could emulate birds flying.
Although written 500 years ago, many of his theories and equations are the same as those used in modern flights.
The notebook’s 18 pages are written in the artist’s backwards mirror script and include drawings of the joints in bird wings, along with the ideas of lift and drag, air flow and gravity.
It is normally kept in Italy but will be on display at the Smithsonian National Air and Space Museum for six weeks.