The growth of cities fundamentally reorganizes economic, social, and political relationships, defines subjects, and reconfigures physical landscapes, although these effects vary in different cultural traditions and natural environments This chapter considers the social and physical environments of urban systems both within cities themselves, and in the rural hinterlands they create and modify. The reorganization of space and of human relationships in cities begins with their initial settlement and construction. Economies are transformed by the concentration of population in cities. Archaeological research points to a similar process in the emergence of Tiwanaku in the Andean high plateau, or altiplano. Spatially divided compounds and barrios provided residence for kin-based or otherwise intimately linked urban communities in Tiwanaku. Childe's notion of the Urban Revolution suggests that the construction of cities and the associated changes in political authority, economic organization, and identities was a rapid if not instantaneous change.