“Carry coals to Newcastle”in other languages

Same idea, different pictures

Each language names a place famous for what you're bringing. Newcastle upon Tyne was the capital of English coal. Tula is the Russian city of samovars, so you don't bring your own. Athens was full of owls, the bird of its goddess Athena; the German Eulen nach Athen tragen goes back to a line in Aristophanes' play The Birds.

Russian also has a version without a city: в лес дрова возить, to take firewood to the forest.