Learn about some of the emerging megaregions of the United States; megaregions are interconnected cities over a vast geographic area that contain more than 10 million residents.

During the mid-20th century, Detroit was the fourth largest city in the United States with a population of over 1.85 million people. It was a thriving metropolis that embodied the American Dream - a land of opportunity and growth. Today, Detroit has become a symbol of urban decay.

Canadian and American cities may appear remarkably similar. They both display great ethnic diversity, impressive transportation infrastructure, high socioeconomic status, and sprawl. However, there is a major difference in U.S. and Canadian urban areas.

An overview of massive urban slums in developing countries. Learn about these slums, called favelas in Brazil, and three specific urban slums.

Learn about urban farming and its potential as the a major development in the future of agriculture.

An overview of several key models used in urban geography to predict and describe the structure of an urban or metropolitan area.

Smart cities are measured by their amount of human capital, which is a factor of an individual's education. The more educated the population, the smarter the city.

We are able to measure how segregated or integrated a city is through the use of the "index of dissimilarity". This equation allows us to identify the disparity within a city and make careful judgments on what the cause of the segregation may be.

A clear and concise overview of the subject of urban geography, a part of the human geography discipline. Learn all about urban geography from this article on the About.com Geography GuideSite.

New Urbanism is an urban planning and design movement that began in the United States in the early 1980s. The goals of New Urbanism are to reduce dependence on the car, and to create livable and walkable, neighborhoods with a densely packed array of housing, jobs and commercial sites. Learn all about New Urbanism from this overview on the Geography site about About.com.

An overview of zoning law and city planning in the United States.

Discover the practical model for agricultural land use surrounding a city, the Von Thunen Model, from your About.com Guide to Geography.

Cities are much warmer than their surrounding countryside due to the phenomena known as Urban Heat Islands. Discover how to combat the heat of the city, from your About.com Guide to Geography.

An overview of the history, growth, and development of suburbs.

The terms site and situation are used in the field of geography to help us understand why a city is located where it is located. Learn about these basic geographic concepts of site and situation.

Learn about law of primate cities and the rank-size rule of urban geography, from your About.com Guide to Geography.

Abraham Levitt and his sons had the greatest impact on U.S. postwar housing through the construction of their three Levittowns, which resulted in over 140,000 homes. Learn about Levittown from your About.com Guide to Geography.

Learn about land-use planning from this overview of the topic from the About.com Geography site.

An overview of historic preservation, the effort to protect historic buildings from destruction, from the About.com expert Geography site.

Learn about the controversial topic of gentrification and its impact on the urban areas as wealthy individuals move into inner cities and gentrify the neighborhoods.

An overview of garden cities, also known as greenbelt cities in the United States. Learn about these 20th century fully functioning master planned communities.

Learn about the phenomenon of edge cities, developed by Joel Garreau, on the outskirts of major metropolitan areas.

The Columbian Exposition was the World's Fair of 1893. Held in Chicago, it showcased many great inventions of the late 19th century. Learn all about the Columbian Exposition from Geography at About.com.

Learn about the City Beautiful Movement of the late 19th century and early 20th century that established the foundations of urban planning and development. From your About.com Guide to Geography.

The About.com Geography Site provides this easy-to-understand overview of Central Place Theory, from contributing writer Amanda Briney.

The CBD or Central Business District is focal point of a city. It is the commercial and office center of the city and usually is the center point for transportation networks.

Learn about the country's largest city in area, from your About.com Guide to Geography.

Find out why we can't compare countries based on their percentage of urbanized populations.

The gravity model can predict the flow of people, goods, or communication between any two places. It's based on Newton's Law of Gravitation and modified for spatial use.

Geographer Jean Gottmann defined the area from Boston to Washington as one huge urban area. Learn what he meant in lumping the area as one.

A listing of the fifteen largest metropolitan areas in the world are huge and always growing.

Geography of Sister Cities: Learn about international city partnerships called sister cities or twin cities from Geography at About.com.