A view from an airplane on a clear day tells us that human settlements are clustered. In modern societies, these clusters are called villages, towns, cities, suburbs, and so on. Charles H. Cooley (1930) held that population and wealth tend to collect at breaks or interruptions in transportation routes. “Both the integration of local activities and the inclusion of the local population in an interregional division of labor are favored by a site at a route intersection” (Hawley, 1950, p. 242). Transportation and communication technologies greatly influence the clustering patterns of human settlements. Also influential, especially in less complex societies, are physical factors such as landform, soils, precipitation, temperature, and natural resources.