An urban area is an area where many people live and work close together, usually in a city. It is where buildings are close together. Urban is the opposite of rural, where farm lands and nature are. Most of the work available in urban areas is office work, rather than agricultural work because the buildings are close together and there's no space for farm lands. There are different urban area definitions for each country. The definitions mostly depend on how populated the country is and if the definition would show a true percentage of how urbanized the country is. For example, in Poland an urban area is any place that has the status of a town, whereas in China it's any district, city, or town with a population density higher than 1500 people per square kilometer.