Just like your other artwork here in Newgrounds, City Watchtowers is a beautiful Painting (Seriously, I could easily see this be more precious than, for example, Mona Lisa). Only problem is the name. "City" Watchtowers? I can't really see a city here, unless you count in those ruins at lower right corner.
Also to hell-diguner below me: I don't think, that's really sky, but more like fog (Look closely at the background and you can see the scenery fade).