The process of European urbanization serves to emphasize the contrasts between urban and rural social organization both before and after industrialization. Within urban centers, however, the continuities between the sixteenth and the twentieth centuries dominated the urban experience. For most of the time, urban dwellers lived in a society whose scale was too large for them to relate to in its entirety, but whose composition enabled them to belong to multiple groupings based on neighborhood, occupation, place of birth, gender, religious affiliation, political or sporting allegiances, or voluntary activity. Each created its own cultural constructs but shared enough of them with others to enable society to function effectively except in times of crisis. This society was constantly shaped on the one hand by the immigrants whose arrival helped to fuel the demographic increases associated with urbanization, and on the other by organs of local and national government, whose priorities reflected the concerns of dominant urban elites. Urbanization reached its peak in the course of the twentieth century, leading to conditions of social overload in terms of population density, demand for services and housing, and an erosion of long-standing social relationships. Since then, urban centers have become even more socially confused as a process of formal or informal deurbanization takes place.