Here's one that just made me scratch my head a bit. IT HELPS TO SEE IT IN LARGE ON BLACK. Makes you think about light and optics.
As said by the photographer, thepres6, on the Flickr caption:
"This is not photoshopped, or layers of different scenes and does not have any other effects applied. It is a dirty window reflection looking into an old building at sunrise. You can also see the sunrise sunlight coming through the 5 front windows in the building."
I say, estupendo.