A suburb is an area of a town or city, a little away from the main part, where there are fewer big buildings and mainly houses, schools and shops. These are called suburbs or 'the suburbs'. Sometimes, cities have suburbs that are over a very large area. The suburbs are still part of the city but may have a different name from the main city or town.
Since the beginning of the twentieth century, cities have spread very quickly and spread farther. Transport in the form of trams, buses and cars mean that people can live farther away from their place of work. This led to the growth of the suburbs. Housing commonly includes detached and semi-detached houses, bungalows and flats. Less houses are built than in the inner city and there is often space for gardens and parks.
As cities grow outwards, they begin to take over the surrounding countryside. Green belts have been created on the undeveloped land around a city to prevent urban sprawl and to prevent the towns and cities merging into one. It also encourages development within the town, while also protecting the countryside. Today, the enormous need for new houses, particularly large detached and semi-detached houses in pleasant surroundings, means that some areas of green belt land have been built on and others are threatened. The reason is that it is cheaper to build on green belt land than to redevelop brownfield sites in older parts of the town or city.