A pavement light above a beer cellar, from the days before electric lighting. In this instance light=window, so as it's set into a pavement the glass is pretty thick and dirty too.
This one is on a very narrow strip of pavement near Edinburgh Castle. Observed during a wander round with Moira and Mick Barrie (mikbee) a few years ago. I remember holding up a couple of coachloads of Japanese tourists who could't work out why I was photographing a dirty pavement rather than my two companions