I have no idea. I'm pretty sure when I built the town hall in Fresh Princeton I'd already been playing a good couple hours, and it took like 7 to build, which may or may not have included breaks while my stone smelted. Probably had similar playtimes for other big buildings but that's the only one I did in one go of such a size that I remember. I've played other games for long periods of time but I don't think anything beats Minecraft. TF2 probably comes close.