This is one of those places where you have to be very creative to get bored.
I have never been in the place which is soooo touristic, but with so many secrets and hidden things to discovery at the same time.
You can walk by busy streets full of cars, people in hurry, tourists with their cameras, shops, noise noise and nose. Then take a few tiny streets and teleport far far from all this. You walked 5 min away and it makes you feel that you are in the different place in the world. Where time stops relaxed, and seems to enjoy silence as you do.
The tourist guides tell you everything about this place, so famous and well known. With history, stories and legends. Whatever, If you get all this or you don't all you need are your own eyes. Just take a walk. You can start in one of those “must see” things which all the people will ask you about, and then just walk. Be your own tourist guide and have fun.