I did this Chicago etch for a friend who lives out there who didn't believe I did the NYC sketch, so this became a half a year late birthday present. 14-20hrs to finish over a long period of time.
And finally, Boston. I posted my previous etches to my favorite social media website, Reddit, and got a great response, which inspired me to continue doing these. Boston is the first etch I did based on requests, and next will be Philadelphia, also by internet request. 12-16hrs.