A city is a relatively permanent and highly organized center of population, larger than a town or village although the distinction between a city and a town or village is not always clear. Cities emerged as complex social and political organizations, marked by complex social structures.
Cities are distinguished by the occupational specialization of residents. Inhabitants of cities are typically socially stratified. Cities can project their power into the surrounding countryside, establishing rule over villages and becoming centers of early empires. Modern cities, while no longer sovereign, are vital centers of human activity, facing challenges in governance, technology, culture, and economics. They are hubs of innovation and cultural importance.