My sweet half bought this book for our (then) 3 year old daughter. We have read several times and one year on she still loves to look at the shadow images and listen to the story.
It's not your regular children's book: the illustrations are not super colourful, instead there is a lot of black shadows (sillhouette). Also, the mother of the child in the story dies and a protective father goes to great lengths to keep his child safe. It is a positive way of introducing concepts such as loss, dealing with loss, growing up and unlimited love.
We have given it to a little friend whose maternal family lives in Venice - we are about to buy another one :)