Londonist has a fascinating little post on coal-hole covers in London. Ornate cast-iron plates to cover holes in the pavement for delivering coal into basements; now obsolete, but still there and subtly ornamental.
I love pieces of urban history like this. Another example of such a thing is the fire insurance plaque, from “the good old days” when fire companies were privately operated, and were paid by your insurance company when they showed up for your fire. If the fire brigade that showed up at your fire didn’t have a contract with your insurance company, the insurance companies had contracts to arrange for transfer payments.
They also provide a useful reference to the Coal Hole pub, near Charing Cross.