City-state

A city-state is a sovereign state that consists of a city and its dependent territories. Historically, this included famous cities like Rome, Athens, Carthage, and the Italian city-states during the Renaissance—but today only a handful of sovereign city-states exist, with some disagreement as to which are city-states. However, a great deal of consensus exists that the term properly applies to Singapore, Monaco, and Vatican City. In particular, Singapore has been referred to by The Economist as the "world's only fully-functioning city-state".