This is the third edition of a four-part series about National Wonders which is supposed to describe the scenarios in which those play a role. As usual when evaluating a building, unit etc. in civ it´s vital to not only look at effects and abilities, but as well at costs, required technologies and most importantly the overall context: In what situation in what kind of game will the building/unit/etc. help me achieve a certain goal? The more situations and different kinds of scenarios there are, the better is the examined object.

There are 14 National Wonders. The series consists of the following four parts:Wall StreetWall Street is the gold equivalent to University of Oxford - again only useful in Ironman/ffa (possible exceptions being rarely industrial teamers and OCC games), meaning longer games. It´s "problem" is that you´ll want to run as much science as possible most of the time. When your research slider is at 80-100%, the bonus of Wall Street is only applied to the remaining 0-20% and the gold the city accumulates otherwise (religious shrine in Holy City, Merchant specialists, corporations etc.). That still can be enough, especially with those other ways of getting gold per turn, to build it. It comes relatively late (with Corporations) and Banks are expensive buildings, if you have a big empire with a holy city or a corporation headquarter, it´s still worth getting it. A Bank is useful anyway in your capital, since even at 20% the gold accumulated there is significant in absolute numbers. In any case it´s a good idea to use any specialists you run in that city (mercantilism, statue of liberty, all tiles worked and still food to grow etc.) to be Merchant in order to take more advantage of Wall Street. With the Grocer, Market, Bank and Wall Street one merchant specialist gives you 9 gold per turn, helping in keeping the research slider as far up as possible.

Forbidden PalaceThe forbidden Palace works exactly like the normal Palace in terms of reducing maintenance costs. It shines especially on higher difficulty levels where those are very high. In an Ironman/ffa the question is not whether you should build it, but where.

How maintenance in a city is calculated:

Distance (D)
Distance of city to (forbidden) palace (whichever is closer) in relation to maximum distance on the map. The maximum distance depends on the map´s wrap, whether it´s flat, cylindrical or toroidal.

Base Value for maintenance (BV)
The base value set in the code for maintenance is 2,5.

Map Modificator (MM)
Depends on size. From duel to huge size: 50/60/70/80/90/100%

Difficulty Modificator (DM)
Immortal and Deity = 100%
Emperor = 95%
Monarch = 90%
Noble = 75%Conclusion

You have no impact on the base value, the difficulty and the map modificator once the game is running. Population is influenced by other factors, which have a higher priority than tweaking maintenance. What you do have an influence on is the distance between the city and the (forbidden) Palace. First by not planting too fast too many cities that are far away from it. Second by planting the Forbidden Palace in the most effective way. Since the effects of the latter and the normal Palace are not cumulative, the Forbidden Palace shouldn´t be too close to your capital. It should be in a city that is close to cities which are far away from the capital. As a rule of thumb for where to build it:Thanks to Zulan for going through the civ code with me in order to determine how the Forbidden Palace works exactly!

IronworksThis isn´t very complicated - Ironworks boosts the production of one city. It comes pretty late, at a time where getting wonders will be more dependant on having the required technology researched than having more production than a competing opponent. Also there aren´t that many wonders left at this stage. Main uses are for building one unit of choice per turn in one city and for getting space ship parts. Put it into a city that doesn´t have huge production anyway already. Put it somewhere, where it boosts the amount of accumulated hammers to a point where you get the unit of choice in one turn. On quick speed that would be around 90-100 hammers for Infantry, Artillery etc., meaning with Forge and Factory (with power) requiring a base production of around 30. If the game is all about Space Race, create a super production city.

As for the prerequisites of Ironworks:

• You should have forges in every city anyway.
• You have to hook coal eventually (even though it gives unhealth with factories, which you have to build in basically every city) for coal plants plants and potentially railroads anyway.
• It might be that you didn´t need IronWorking for a long time, but at this point in the game you´ll have it.

Moai StatuesIn an Ironman/ffa you will eventually want to work every tile you can get your hands on. That includes all sea tiles. Moai improves those significantly. A city with many coast tiles won´t be doing a lot of production, Moai helps a lot here. In combination with a Golden Age you´ll get 2 hammers on tiles where you otherwise wouldn´t have gotten any, making it a great production city in those times and a decent one in other times. Great combo with Dutch dikes

Plan ahead for Moai - when marking spots for potential cities, try to get as many sea tiles as possible into the fatcross of one city. If it doesn´t have any base production then, just slave other stuff you´ll need eventually anyway and put the overflow into Moai. Especially with stone you´ll slowly but surely get it. There is no need to get it too fast anyway since in the beginning you won´t be working all tiles, but rather be slaving more to get the basic buildings. Moai should be done till you switch away from Slavery (around researching Democracy). If the city has some production and you got stone, you can build it quicker.