A city is an area consisting of numerous institutions, residents, industries, and businesses supported by large infrastructure and a dense and diverse population. A city can be framed in numerous ways. For example, it can be thought of as an economic system, in which all social relations stem from a market economy, and the city is produced and shaped by the market. A city can also be thought of as a state of mind, in which all people who live in the city share the same consciousness. Similarly, it can be seen as an aggregation of different social/cultural forms, making cities a center for heterogeneity. Finally, a city can be seen from an architectural perspective, as a conglomeration of masses and spaces. As Henri Lefebvre states, "a city is, therefore, whatever is experienced, known, represented, constructed, or destroyed as a city."