Leonardo da Vinci has been known for his paintings such as the Mona Lisa and The Last Supper. But did you know that Leonardo has interest in sciences and in engineering? Check out his blueprints of various weapons like cannons and ballistae in his Codex Atlanticus which can be read online. The Codex Atlanticus is a 1119-page collection of papers.
You can read it online via this link.
(Image Credit: Kottke.org)