A city with no walls (known as The Rose sanctuary) in a world of grey is about a city of people that do not hide behind walls and although titans still try to kill them they still enjoy their lives. How ever there is a reason why this world is called Grey.
These are some pictures I did digital and paper, you get the idea. I do, in fact, own the art. If you do want to use, I'm more than happy to let you, just credit me please.