Very pretty indeed. I love the way you define the roads using negative space rather than drawing them in individually - that really helps minimise the visual clutter. The structure in the middle is a little mysterious, and without shading I needed to work a bit harder to figure out where the vertical heights were, but I think you did a fantastic job of it. You're line work is beautiful - I know all too well how hard it is to get a pen drawing to look that clean. Was this done pen on paper or with a tablet?