A story about Leonardo speaks to both his love of nature and fascination with flight. When at a market, Da Vinci would often pity the cooped-up birds that were on sale, plunk down the asking price for them, then release them into the air. Leonardo had a legendary obsession with the flight of birds and how understanding the mechanism could lead to the creation of a human flying machine.
Leonardo filled his notebooks with hundreds of drawings and thousands of words of observations on the subject of flight. A full-scale rendition of an aerial screw–touted as a precursor to the helicopter, though biographer Walter Isaacson says it was probably designed for a theatrical production–is on display on the grounds of the Clos Lucé.