i know this has been discussed before in another thread, but this thread is NOT THE SAME. so, when I capture a enemy city, do I destroy all of their buildings? or only some? will there be culture penalty? or is there no need to destroy it? there seems to be many things that need to go under consideration...so I need some advice here.

ie. I played as the Macedons and just conquered Athens, I destroyed their governmental building and built my own *pat myself on the back* BUT,what do I do with the Koinon Hellenon's barracks, traders, blacksmiths, and all those other buildings?? and even more strange is when I opened the city details summary there were no signs of culture penalty!?