Zoos in some cities have a lot of public art, some designed for the zoo, some left over from city-wide art competitions.
I just wanted to mention that, for those of us still trapped in quarantine (or about to be re-trapped after the coming COVID spike hits in some states (looking at you, Georgia)), you can make your own public art and put it in your home. Then, when you’re bored, you can box it all up and ship it to a friend to hide throughout their house while you get a box from theirs. All sorts of fun can be had.
(Just be sure to either let the box sit long enough for any latent viruses to degrade, or disinfect it as you unpack.)