Cities are larger settlements and have greater economies than the colonies in the game. Like colonies, cities are also not plunderable but only conquerable. However, different than colonies, players can not establish cities: they exist at the beginning of the game. Conquering cities is currently the only way to earn diamond for the kingdoms.
Diamond is earned hourly from a city and is added to the treasury of its ruling kingdom right away. The amount of hourly diamond gain varies among the cities. Some cities earn more diamond than the others and thus, they are more advantageous when conquered. There is no upper limit for the number of cities that a kingdom can rule simultaneously.
Cities in the game are evenly distributed on the world map to prevent injustice among the players. There are currently 43 cities in the game.
See the List of Cities