In 1643, Dutch artist Isack van Ostade completed a painting titled A Village Fair, With a Church Behind. Then more than 350 years later, the oil painting went through a restoration in preparation for the 2015/16 exhibition "Masters of the Everyday: Dutch Artists in the Age of Vermeer." As restorer Adelaide Izat carefully stripped the old, yellowed varnish from the painting, she noticed that a section in the lower right part of the painting had been painted over at some point. Someone had added bushes to the scene, but why? When the more recent paint was removed, it revealed a man relieving himself on the side of the road! The image is not explicit, but it is clear what he is doing. Who decided that the image needed to be covered up? It was probably done during a previous restoration in 1903, which you can read about at Mental Floss. The history of art sometimes tells us about the changing state of public sensibilities and censorship than the art itself.