Researchers found out that the smile is consist of 83% happy, 9% disgusted, 6% fearful, 2% angry, less that 1% neutral and not surprised at all. New theory for Mona Lisa's smile states that the girl in the painting suffer from muscular atrophy on the right side of the body that's why her smile is like that. The facial expression also seems to change in different angle. Yes, this painting is truly interesting the smile may really mean something but no one knows the truth. So I guess we should just be satisfied and enjoy this magnificent work of art
No matter whats the reason behind the smile. The bottom line is Leonardo da Vinci did a great job in this painting. And I know no one will disagree that this painting is indeed a very big and important part of history. Regardless of the person in the painting, the reason for its smile and other mysterious speculations in it. It will always be the one of the most amazing paintings in the whole wide world. We should be thankful for it is made and we were able to witness its beauty.