How does culture defense work?

[Zanmato]

I think the idea behind walls is that you can quickly establish a defence for a new city without waiting for it to build up significant culture; so in that sense walls are a stop-gap measure.

That's all very well until Gunpowder units appear then you get no bonus at all. You can build a castle well into late game but they offer very little by then, only +1 culture as they are only effective against pre-gunpowder too.

 

[Clownfish]

Will bombarding shrink the city's general culture and cultural borders? All accumulated culture lost?? Can't be, cuz then it would be too easy to stop someones Cultural Victory.... But then again, when capturing a city, it will usually have pretty crappy culture... right? Why?

 

[gunkulator]

Bombarding has no effect on culture or borders. It just lowers the defensive bonus. Left alone, the city's defense bonus will creep back up again.

When you capture a city, you start over again at zero culture points. Also, all the culture producing buildings are destroyed. Wonders survive but they lose their ability to produce culture. Basically, culture must be generated by your civ. There is no way to capture or inherit the culture built by another civ.

 

[Codeman]

so i build walls early to get defence bonus, then later when my culture is high my defence bonus is from culture not walls. makes sense to me since after a city is a certain size walls all the way around and high enough and strong enough would not be practical.