Cities are the main creators of economic wealth, generating over 70 per cent of the world’s Gross Domestic Product (GDP). Most industries and businesses are located in or within immediate vicinity of urban areas, providing city residents with jobs. Because most employment opportunities are within urban areas, cities attract large parts of a country’s job seeking population. This is especially true in developing countries, where an increasing share of economic activities take place in cities, and the differential between urban and rural wages is growing.