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Naturalists may be purchased in your city with 
Faith after researching the File:Icon Conservation.png Conservation Civic, and can be used to designate National Parks. Creation a National Park consumes the Naturalist unit.
Requirements
National Parks can be built on a cluster of any four contiguous hexes that meet the following requirements:
- The tiles must be natural wonders, Mountains, or a tile with an Appeal of Charming or better.
- All four of the tiles must be owned by the same city.
- The tiles must form a (vertical) diamond shape (not a slanted diamond).
- No tile can have an Improvement or District on it.
With the Naturalist active, zoom out and view the map - any usable areas will be highlighted in white. Use the Appeal lens to find areas that are almost usable, and might just require you to purchase another tile, or plant a forest to raise appeal.
Notes
- A National Park's
Tourism output is equal to the total Appeal of all the titles included in the Park. Creating a National Park will also give your Civilization extra Amenities. You will receive 2 Amenities in the city that owns the park and 1 Amenity towards the 4 closest cities in your empire.
