City flipping uses both total culture and culture income. Even when you build that library you only get 3 culture points. If that nearby enemy city has a library that is 1000 years old then that library has more culture points then yours does. You risk a flip. Bomb that city. Destroy those culture points. Then your city won't flip. I just love artillery! Twenty artlillery pieces can give you a big edge. Is that stack of cavalry near your city causing you trouble. Bomb it. Reduce them to one hit point. Then you can safely attack out of you city with infantry and not worry about them being caught in the open. And the AI NEVER attacks with 1 HP. They always retreat to heal up.
In my current game I'm the Americans with the Germans on one side and the Japanese on the other side. There are also the Zulus, Russians, Aztecs, Romans, French and Indians. Both the Germans and Japanese are always attacking me. These 20 artillery pieces have gone by rail from one end to the other end to stop an attacking force. Even though the entire world is at war with me, (I had MPP's but they had other MPP's and decided to honor them and not mine) I've fended off rebeated attacks and managed to capture 3 of the 10 German cities and 7 of the 12 Japanese cities. I now have tanks and am about to take 2 more German cities and two more Japanese cities. I also have a couple of carries that I use to hit the luxuries and resources of the other countries.
Bottom line is that bombers and artillery are a real asset. Use them. And reduce that culture in your enemies cities.
In my current game I'm the Americans with the Germans on one side and the Japanese on the other side. There are also the Zulus, Russians, Aztecs, Romans, French and Indians. Both the Germans and Japanese are always attacking me. These 20 artillery pieces have gone by rail from one end to the other end to stop an attacking force. Even though the entire world is at war with me, (I had MPP's but they had other MPP's and decided to honor them and not mine) I've fended off rebeated attacks and managed to capture 3 of the 10 German cities and 7 of the 12 Japanese cities. I now have tanks and am about to take 2 more German cities and two more Japanese cities. I also have a couple of carries that I use to hit the luxuries and resources of the other countries.
Bottom line is that bombers and artillery are a real asset. Use them. And reduce that culture in your enemies cities.