I think I’m going to start taking pictures of interesting manhole covers. These objects are all over the place, but we rarely pay any attention to them, for all that they tell interesting stories in sometimes artistic ways. This one reads “P.S.CO. / EG / COLO.” Presumably that’s Public Service Company of Colorado (now Xcel Energy). My guess is that EG is the foundery that made the cover. This one is in downtown Denver, south side of 17th Street, 800 block, just north of Welton. It shows a lot of wear (some letters have broken off).
Manhole Cover – P.S.CO. COLO.
287 view(s)

FYI
http://www.danheller.com/manholes.html
http://www.covers-to-discover.com/en/
http://www.sewerhistory.org/grfx/components/mhcvr1.htm
These are just a few of the sites I found on Google. It looks like the world of manhole cover photo collectors is in dire need of your contributions from Denver!