Siegfried Woldhek knows faces -- he's drawn more than 1,100 of them. Using sophisticated image analysis and his own skills as an artist, he's come up with a fascinating discovery about Leonardo Da Vinci.

Leonardo Da Vinci's life and work is well known -- but his own face is not. Woldhek used some thoughtful image-analysis techniques to find what he believes is the true face of Leonardo. Here, he walks viewers through exactly how he did it.