Is it possible to improve the fortification level of a walled city? So if city "X" has a level ("size") 1 fort, how do I get it up to size 2 and higher?
I'm guessing the answer is "no" but I thought I'd check. The fortification level does not seem related to the size of the city, eg Rome. I assume that each city's fortification level is assigned by the scenario designer.
Also, the "build walls" decision mode option seems to only mean "rebuild walls" i.e. repair already-existing walls that have been breached in a failed siege. Is that the case? In the game I'm playing at the moment, this option is never enabled so I'm not quite sure where it applies. Certainly I can't find a case where I can add walls to one of my unwalled cities, which would be really handy...