Manhole Covers

A couple of years ago I visited Lisbon with my daughter. 

We went to the former Expo, wich was held in 1998. 

I spotted a manhole cover made especially for this event.

 Since that time I looked in cities for a manhole cover showing someting about the city.

Don't think I only look at the ground :)

 Copenhagen

Copenhagen

 Copenhagen

 Prague

 Berlin

And this one is in my hometown Nijmegen

On Pinterest I have a board of manhole covers.