[citation needed] The small remaining power held by individual cities becomes a target of numerous outside influences such as large corporations and real-estate developers.
[7] Progressive regimes respond to the needs of lower- and middle-class citizens and environmental groups to keep things as they are, rather than to economic growth.
[8] During the westward expansion period of the 18th and 19th centuries, numerous areas were settled as trading posts along major transportation routes.
Sometimes called “walking cities” because of their small size and limited mode of transportation, these areas were economic centers that had not yet experienced the influx of population that came with industrialization and immigration.
[9] As industry and transportation technologies improved, American cities became centers of production and the process of urbanization began to take place.
Part of the urban population growth was fueled by an unprecedented mass immigration to the United States that continued unabated into the first two decades of the twentieth century.
[10] Cities became locations of opportunity that drove rural to urban migration, but the waves of people also led to congestion, overcrowded housing, undesirable living conditions, poor sanitation and major health epidemics.