Bill Gates' Leonardo da Vinci journal
Included in Gates' mansion's many rooms is a huge domed library filled with books. Gates is an avid reader, and he reportedly hired a rare-books dealer to stock his library for him. Among his possessions is Leonardo da Vinci's "Codex Leicester," a 15th-century manuscript that Gates bought at auction for $30.8 million in 1994. Of the 30 surviving Leonardo da Vinci scientific journals, the Codex Leicester is the most famous.
