In a radial structure, main roads converge on a central point.
This form could evolve from successive growth over a long time, with concentric traces of town walls and citadels marking older city boundaries.
In more recent history, such forms were supplemented by ring roads moving traffic around the outskirts of a town.
The most populated city proper is Shanghai A city is distinguished from other human settlements by its relatively great size, but also by its functions and its special symbolic status, which may be conferred by a central authority.
The term can also refer either to the physical streets and buildings of the city or to the collection of people who dwell there, and can be used in a general sense to mean urban rather than rural territory.
It may be adapted to its means of subsistence (e.g. And it may be set up for optimal defense given the surrounding landscape.
Beyond these "geomorphic" features, cities can develop internal patterns, due to natural growth or to city planning.
Archaeologists refer to this area by the Greek term temenos or if fortified as a citadel.
Today cities have a city center or downtown, sometimes coincident with a central business district.Cities serve as administrative, commercial, religious, and cultural hubs for their larger surrounding areas.A typical city has professional administrators, regulations, and some form of taxation (food and other necessities or means to trade for them) to feed the government workers.In others, such as in the United Kingdom, city status is awarded on local criteria.According to the "functional definition" a city is not distinguished by size alone, but also by the role it plays within a larger political context.Present-day cities usually form the core of larger metropolitan areas and urban areas - creating numerous commuters traveling towards city centers for employment, entertainment, and edification.