Cathedral of Learning, Pittsburgh, PA
The second star trail shot (first one below). This one is made up of 120 shots, each taken at 30s, f/3.5, ISO 100. You can actually see some light trails from planes as well.
I completely overexposed the building while trying to expose for the stars. Had to set a different exposure for the building at the end and then overlay it on the star trails image. I was afraid the street lights would cause a lot of lens flare, but much to my surprise, they were not too bad (you can still see some if you look close enough). All I can say is, Canon 10-22mm is a very well made lens!