I was trying to figure out a way to easily make large maps for 'reference' rather than for battle, and realized that I could just create a terrain that was a city map. I took a public domain map of Paris from the 1500s and created a repeating tile (in two different sizes), then extracted bits of the map for object assets (bridges, trees, map ornaments, etc.). There's also a path that matches the streets on the map.

The "battlements" wall seems to make a decent city wall. If you cut through the city with the water tool, you can kinda see the buildings underneath the water if you zoom in really close... not sure what to do about that, but who really wants to be THAT close, right?

The sample attached here is a quick 5 minute map job.

The original map, by Olivier Truschet and Germain Hoyau, can be found on Wikimedia Commons if you search for "Plan de Paris vers 1550 color.jpg."

("This work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 100 years or fewer. ")