Sid Meier's Civilization VI is an entry in the long-running Civilization series of strategy games. It retains most of the features of Civilization V (with expansions), with the World Congress being the only significant omission. On top of this, the game adds a new victory type (religious); separates technological and cultural development into separate trees, with advances being divided between technologies and civics; "unstacks" cities, with development via specialized districts; makes happiness more local, and introduces housing as a restriction on city growth; reforms the city-state system to give a unique bonus to every city-state; overhauls the great people system to give unique powers to each great person; along with a host of other changes.