National Park mechanics
National Parks are unique in several ways:
- They are established not by standard building units, such as a Builder or Military Engineer, but by the Naturalist - a special civilian unit that can only be purchased with Faith. (Canada can also use its unique unit, the Mountie, to establish National Parks.)
- They cover not a single tile, but a cluster of four contiguous tiles that meet the following set of specific requirements:
Note that in order for the Naturalist to establish the future park, they must be able to move onto one of its tiles! As Mountains and many natural wonders are impassable, this may present a bigger problem than it seems.
Since water tiles do not have Appeal ratings, you cannot establish a National Park with a water tile included. However, since natural wonder tiles always have a Breathtaking Appeal of 5, natural wonders on water tiles adjacent to the Coast (Galápagos Islands, Great Barrier Reef, Hạ Long Bay, etc.) can still be incorporated into a National Park.
Parks provide benefits both to their parent city, and directly to your empire. A National Park provides Tourism equal to the total Appeal of all the tiles included in it, as well as 2 Amenities to the city that owns it and 1 Amenity to the four closest cities in your empire. Note also that tiles within the park can still be worked by nearby Citizens (if, of course, they are actually workable), and thus add yields to their parent city.
Establishing National Parks can turn into one of the greatest challenges in the game because of their strict placement requirements. However, the result is well worth the effort, especially for players pursuing a Cultural Victory. The combined Tourism output of a single National Park could range from 8 (if all tiles have the minimum required Appeal of 2) to more than 24, not counting the bonuses from Computers. Note that, similar to the Chemamull, the Tourism provided by a National Park is dynamic and will constantly adjust accordingly depending on the Appeal ratings of the 4 tiles within it. Therefore, it is possible to have a National Park that provides negative Tourism if you surround that park with Appeal-lowering Districts and improvements.
Planning for National Parks
The key to establishing National Parks is, as with everything else in this game, planning. You should mark the areas where you want to establish National Parks in the future, and avoid constructing districts on them (because once placed they cannot be removed, unless the parent city itself is destroyed). Furthermore, you should avoid placing Appeal-diminishing districts (Industrial Zones, Encampments, Aerodromes and Spaceports) nearby, and try to build Appeal-raising districts (Holy Sites, Entertainment Complexes, and Theater Squares). You can also build the Eiffel Tower or use the Great Engineers Alvar Aalto and Charles Correa in the city closest to the site of the National Park to further increase the tiles' Appeal.
The new Preserve district can provide valuable bonuses to National Park tiles. If you plan its placement well, you can use two of the tiles it affect for establishing a National Park. First, it will increase Appeal there by 1; second, its buildings will provide additional bonuses to these tiles (if they are workable, of course). Remember that the only requirement for both using Preserve bonuses and establishing parks is for the tiles to have no improvement or District on them. Thus, you can have any other feature, such as Woods or Marsh (although Marshes and Rainforests diminish nearby Appeal, so you should aim instead for wooded areas). You can even plant Woods using Builders! And of course, you can build improvements on the tiles of the future park, just remember you will need to remove them later.
Prime locations for establishing National Parks are natural wonder tiles - they are automatically considered valid, and they raise the Appeal of nearby tiles, thus helping them achieve the minimum requirement. It is interesting that, when designated, these National Parks receive the name of the natural wonder itself (something like "Yosemite Valley National Park"), which is very much like real life! Irregularly shaped multi-tile wonders such as the Eye of Sahara or Mount Roraima are ideal locations for parks, as long as you manage to include all the necessary tiles in the territory of the same city, and you will be able to work them. For added effect, drop a Preserve nearby for even more yields!
Mountains are also a good location for National Parks, especially when they form long vertical chains. The Mountains and most of the nearby tiles will already be valid sites, and you will just need to include them in the territory of a nearby city. Just remember that you will always need one non-Mountain tile (with an Appeal of Charming or higher and no improvements or districts on it) from which the Naturalist can designate the National Park.
Finally, as the territory of cities strong in Culture grows, you will find you've reached tiles far from City Centers, which will often have no other "civilization" use but to be turned into a National Park. These are ideal locations (as long as they fit the requirements, of course), because they will make use of land which is otherwise useless. Unfortunately, you have basically no control over acquiring faraway tiles like that, so you will just need to wait and hope that no other civilization will decide to found a city there.
Creating Suitable Land for National Parks
Despite all your planning, you may discover that when selecting your Naturalist the coveted white pattern doesn't appear anywhere. Thankfully, you can manipulate terrain features and purchase tiles to create places for National Parks. Here is what you should do:
- Analyze your land. Remember, you're looking for four neighboring tiles that create a vertical diamond shape. If you have lots of Mountains or a natural wonder, these are the places where you should start your analysis, but remember that you always need at least one passable tile there. Next, look at coastal regions - all of these have naturally higher Appeal ratings, so chances are you will find spots which almost fit all requirements.
- Identify problems. Take a careful look at all potential spots, and see what hinders them from becoming suitable. Chances are the Appeal of one or more tiles isn't high enough, there is an improvement on one, or the tiles you need aren't part of your territory. Of all these, improvement problems are the easiest to solve - just take a Builder and go remove the problematic improvement!
- Increase Appeal. The second most common problem when creating National Parks is that one or more tiles in your target location don't have the minimum Appeal of Charming (2). However, you can fix this by manipulating terrain features - remove existing features which diminish Appeal (that is, Rainforests and Marshes) and/or plant Woods. Any tile with Woods gives +1 Appeal to adjacent tiles; it also gives +1 to its own tile, if the Woods are Old-grown (that is, placed there from the game itself, and were included into your territory when you discovered Conservation). If you place Woods on all four tiles, you can potentially raise their Appeal by 4, which should be more than enough. Finally, in Rise and Fall you can use the new City Park improvement for a +2 Appeal boost; just remember to build it right next to, and not on the potential National Park. (Unlike Woods, a City Park will block the creation of a National Park.)
- Buy tiles. The final and most difficult requirement to satisfy is that all four potential tiles must belong to the same city. Many times one or more tiles will belong to a neighboring city, so you will have to enter citizen management and swap the tiles so they all belong to the same city. Other times, tiles necessary to complete the pattern will be outside your borders. In this second case, and if the missing tiles are within 3 tiles of the city, all you need is to purchase them. However, if they are too far, there's nothing you can do but wait for the city to expand to them naturally.
Forcing the game to select desirable tiles
Sometimes the game engine does not select the tiles a player wants for the National Park. The problem is not that it cannot be built there, but that the game decided the park outlined in white is better. To force the game to select desirable tiles it is required to change something to break that outlined park, like adding an improvement or temporarly changing tile ownership.