Windmill

Windmills are large buildings resembling gristmills, with a vertical construction since the 12th century. Though more expensive, they're able to perform the actions of water-powered mills, in regions where there is too little water, where rivers freeze and in flatlands where the flow of a river is too slow to provide the required power.

However, windmills require a sufficient source of wind, which can be obtained in steppelands or in places adjacent to salt-water seas that have been denuded of trees. Hexes that contain single hills, that are as developed as type-3 or better hexes, may also serve. Thus, although a type-6 hex can theoretically support a windmill, location also matters.