For those interested, for Bucharest there's this [1] blog-post with a few photos of some old manholes. In here [2] there's a list of links from the same project to posts that present some old stuff from and around Bucharest (the text is in Romanian, but there are lots and lots of photos that are self-explanatory).
Locally, the challenge is an interesting, somewhat artistic, usually (but not always) urban picture. I've already taken a picture of most designs I see, after all. In any other city, I'm catching the design first. (Tromsø, Norway has a reindeer!)
I'm not all that surprised there is a website to catalogue them and am always kind of happy to be reminded that others have the same fascination.
She uses manhole covers to create prints, "Raubdruck" means "pirated edition" but literally it's "stolen print"