Or: the fake windows of Turin.
While walking around Turin, sooner or later, you're going to notice that some of the windows on various old buildings windows aren't real. Why this should be, I don't know. I didn't ask at the time, and I can't find anything about it on the internet. Some are quite convincing and take a second or third glance before you notice them. Others, not so much.
But perhaps my favourite fake windows were some that aren't painted on. Along a narrow street, the sunlight of one set of windows was reflected onto a window-less building on the other side of the street.