As I mentioned earlier, my friend Jeff and I took a walk along South St. one morning while we were in Philadelphia. For a few blocks along South St. and along some of the side streets there is a wonderful, weird installation of mosaics in, on, and between a bunch of buildings and vacant lots. The artwork is by Isaiah Zagar, who has been making these murals since he moved to Philadelphia in the late 1960s. I really enjoy this type of art and have made trips to places such as the Heidelberg Project in Detroit and the Garden of Eden in Lucas, Kansas, and plan on visiting Fred Smith's Concrete Park in Wisconsin later this year.
I could say more but I'll just let the pictures speak for themselves in the photo gallery.
More about Isaiah Zagar and his art:
Philadelphia People profile.
Pew Fellowships in the Arts biography.
Philadelphia Weeklyarticle about protecting murals, and a reprinted biography from the same publication.
Photos from Agility Nut.