I actually sketched this a few months ago. I had always heard of the Art Institute and meant to go check it out, and then one day on a walk, stumbled across it. They have a fantastic view from their patio/courtyard, and it was primarily empty!
Periodically, I get brave and decide to try sketching only with pen. This particular pen has a very nice olive green color, (the subtlety of the color is lost in my scan unfortunately).
Whenever I get a particularly nice piece of paper, or a fancy pen, I always suffer from a kind of "stage fright", as if I am being judged by my art materials. I think this is why some of my favorite sketches are done on cheap paper, with pencil. The end result is that I hoard. I really need to get over this because such an attitude really defeats the purpose of having quality supplies.