I searched and haven't seen this mentioned here yet, but it seems a Japanese TV show has identified the real-world inspiration for the walled cities. I found this video on my Tumblr this morning.
It's the town of Nördlingen, Germany, seen here on Google Maps. German laws are very strict about privacy so Google Street View doesn't really work. But there are some ground-level panorama photos and the insides of some buildings. And Google Earth has 3D models of some of the area if you want to enter flight simulator mode and go zooming around.
I don't understand Japanese but I'm assuming this is Isayama's actual source of inspiration rather than just a coincidence since the architecture is such a close match, the central church looks darn near identical to the HQ in the Trost arc, and the fact the village center is surrounded by a high wall.
One wonders if any fans of the series live there and what they thought when they first read/saw it.
Nice find, that's cool.
Cool indeed, thank you for posting it.
Inspired by Walls in Germany that give the series
kind of a new meaning so do the
Titans represent Commies or Capitalists?
Just noticed all the cool Post Icons
BUT NO "FLÜGEL DER FREIHEIT" (Wings of Liberty) Icon
for Shingeki no Kyojin