Located in Wiesbaden, Germany. Via the Manhole Porn subreddit (I kid you not - and despite the name totally SFW).
Reposted from last year to add this manhole cover -
- found by John Farrier and posted at Neatorama. The artist has a gallery of similar "street art," so I'm not sure if the manhole cover was painted in situ or digitally altered. I suspect the latter - but still clever.
Reposted from 2018 to add this manhole cover that provides a map of Oklahoma City, with a rivet to show where you are. At the discussion thread it was mentioned that this style of manhole cover was used on sidewalks, not in the street where you would have to dodge traffic to view it.