As this manhole cover is viewed as a mundane object, a lot of people were surprised that it may also be called a work of art. People like this kind of manhole cover art.
There are many such manhole covers on the World Wide Web, including a lot of custom-made manhole covers.
“Grate Wall Medallion” (fiber art)
“City of Orlando” (detail of wall relief)
See Bobbi Mastrangelo’s “Grate Works of Art”: http://bobbimastrangelo.com