Codex Leicester

The Codex Leicester, a collection of scientific writings on astronomy, the properties of water, rocks and fossils, air and celestial light by da Vinci is currently the only document by the scientist/artist to be held in private hands. In 1994, Bill Gates bought the 72-page manuscript at an auction for $30.8 million. The Codex is put on public display once a year in different cities around the world.