There are few people who do not enjoy the magic of a great city. But urban sprawl deprives the individual of this magic if he is not lucky enough, or rich enough, to live close to a large centre. Most people live in the suburbs and have no more than occasional access to the city's life.
This problem has led to considerable research in USA on the optimum size of cities and the distribution of their facilities. One such study showed that cities with more than 50,000 people have a big enough market to sustain 61 different kinds of retail shops and that cities with 100,000 people or more can support sophisticated jewellery, fur and fashion shops as well as a university, a museum, a library, a zoo, a symphony orchestra, a daily newspaper and a radio station. A population of 250-500,000 can, in addition, provide funds for a medical school, an opera and TV networks. Such studies aim to increase decentralization of activities and entertainments in cities, so that they are accessible to more people.