Cities are dense forms of human settlement designed to include a variety of infrastructures from housing and transportation to communication, sanitation and utilities. Differentiated from rural areas via high population densities and planning complexities, cities are created through processes of  rapid urbanization related to greater employment and entertainment opportunities offered in urban areas.

Today, over half the population of the world lives in cities with younger generations continuing to move to these urban centers in pursuit of a diversity of jobs, experiences, and lifestyles. The following collection of infrastructures, people, fixtures, and elements pulls together a large variety of interrelated aspects of cities around the world.