Not only is her smile strange, just about everything about her is strange.

Leonardo did not give this, or any other of his paintings, a title. He simply said it is of a Florentine lady.

Before we dive into the nitty gritty of what lies behind the painting, it never hurts to point out that the first people to see Mona Lisa outside Italy lived in Amboise in the beautiful Loire Valley.

He imagined vertical flight long before the necessary technology to make it work saw the light of day.

It is not too fanciful to say that the world owes a huge debt of gratitude to Francis I, King of France for Leonardo's Notebooks, or at least some of them.

Francesco Melzi was an Italian aristocrat. His family took the name from their home town, Melzo near Milan (Francesco has a street named after him).

In 1494 Leonardo da Vinci started working for Ludovico Sforza, the duke of Milan.

Dendrologists, who study the growth patterns and structures of trees, say that Leonardo's Rule of Trees is spot on.

After more than five hundred years, thousands of books and millions of words written about Leonardo da Vinci, there are not many mysteries left surrounding him.