Originally posted by Flare |UKCS|:

You are fully allowed to do the big cities, but its up to your PC's ability to accommidate your designs, the game doesn't stop you, its your hardware that prevents it, no amount of optimisation will allow for unlimited builds, eventually you will get limited.
Game is not advertised as a unlimited city building game, its a survival game where you need to beat x bosses to win.

With my rig I shouldn't have any problems to handle the biggest buildings, it's a top tier gaming pc. I don't want to make Rome or something like that, just a tiny cute city, maybe 3 or 4 houses and a viking longhouse.