Urbanization: The process by which towns and cities are formed and become larger as more people begin living and working in central areas.
Industrial Revolution: A period of major industrialization that took place during the late 1700s and early 1800s. It was characterized by developments in textiles, iron making, steam power etc., leading to significant shifts in population from rural areas to cities.
Great Migration (1916–1970): The movement of 6 million African Americans out of the rural Southern United States to the urban Northeast, Midwest, and West.