Favourite piece of art-work?

What’s your favourite piece of art-work? Why do you like it? Is there a particular history or memory behind why you like it?
Mine is the Peaceable Kingdom by Edward Hicks. As I’ve come to understand the art-work (and this is probably a very misguided view and a very wrong retelling of its story), Edward Hicks was a Quaker in the 1800’s and as a man of religious background, he wanted to follow his passion for painting but he didn’t want to offend the church, so he painted the scene of the Peaceable Kingdom, not once, but at least 60 times, each time slightly differently, reflecting a different part of his life that was important at the time, i.e his son in one painting is clearly prominent.
(apologies for the long-ness of that) What about yours?