By this time five percent of Americans lived in urban areas (places with more than 2,500 people) which were mostly small villages. At the end of the colonial period, Philadelphia was the largest city, holding a population of about 30,000—second only to London, England. By the 1800's industrialization had produced a notable growth in American cities, 35 percent of Americans now lived in urban areas mostly in the Northern half of the United States. Members of the rich, poor, and middle class were all represented in these emerging cities. Urbanization produced three different types of cities; commercial centers, mill towns, and transportation hubs. These new urban environments provided many changes, they were a source of hope, conflict, and adjustment especially to new immigrants. Cities arose as sources of diversity and pluralism. Economic and social forces that changed city dynamics included industrialization, transportation, and population growth. During industrialization periods cities were centers of industrial growth, they also concentrated capital, workers, and consumers. Most cities had a