Urban sprawl
Urban sprawl is the name of a city growing in areas which have been unpopulated so far. This growth happens once the city has reached a certain size. In general, this growth also happens without regard for the planned growth, called urban planning. In the Middle Ages, there was the benefit of being protected when people lived inside the city. In modern times, there is no such benefit, and the only disadvantage is that it takes longer for people to get to the city center. People disagree about the exact definition of urban sprawl and how to measure it.
The term urban sprawl is a political one, and almost always has a negative connotation (usually that of the uncontrolled growth of a city).
Urban Sprawl Media
A typical suburban development in the United States, located in Chandler, Arizona
An urban development in Palma, Mallorca
Measures for urban sprawl in Europe: upper left the Dispersion of the built-up area (DIS), upper right the weighted urban proliferation (WUP)
This picture shows the metropolitan areas of the Northeast Megalopolis of the United States demonstrating urban sprawl, including far-flung suburbs and exurbs illuminated at night.
Traffic congestion in sprawling São Paulo, Brazil, which, according to Time magazine, has the world's worst traffic jams
Low-density housing placed between large farms in an exurban community in Tennessee
Clustered commercial strips like this one in Breezewood, Pennsylvania are common in outer rural exurbs and suburbs in metropolitan areas.
Walmart Supercenter in Luray, Virginia