Each city improvement should have specialist slots. The specialist slots will be able to enhance the function of the improvement. The longer the specialist stay in that improvement, the greater the enhancement. For example, the ultrasonic fence improvement will accumulate one specialist point per turn for each specialist staffed in this improvement. When a total of 25 points have been accumulated, the ultrasonic fence improvement can be upgraded. There will be three options for upgrade. Each option will take players down a different affinity. Upgrade option 1 might take players toward harmony affinity, while option 2 may take players toward supremacy affinity. Having been upgraded once, it will take the same ultrasonic fence 75 points for the next upgrade to happen. In another word, successive upgrades to the same improvement will require more and more specialist points. I think this is a wonder feature that will allow players greater options to customize our civilization. It will also address something that I found missing in all reincarnation of Civ games. All great civilizations in history have at least one great city that stands out because of its specialization which leads to excellence in a certain field of endeavor. Venice, and Amsterdam were great trading centers of Europe. New York, Hong Kong, and London are great financial centers. Milan is the center of fashion, and Silicon Valley the center of technology. These specializations are made possible by concentration of specialists. Civ games to date do not have mechanism that models this important aspect of civilization. I think my suggestion will correct that.