Previous: Diazonium Salts & Nucleophilic Aromatic Substitution: Crash Course Organic Chemistry #47
Next: Emmett Till: Crash Course Black American History #34



View count:83,032
Last sync:2023-01-06 02:45
According to the UN, people living in urban places now outnumber those in rural areas — which is a pretty new phenomenon for many parts of the world. So today, we’re going to discuss factors that have led to this shift in populations from rural to urban residences (known as urbanization), and we’ll examine the historical and structural systems, like colonialism and Central Place Theory, that have influenced the cities we see today.

3:20 On the map here we incorrectly placed the Shanghai marker where Guangzhou is located.


Knox and Marston 2016: Human Geography Place and Regions in a Global Context. 7th Edition. Pearson
Marston et all. 2017. World Regions in a Global Context. Peoples, Places and Environments. 6th Edition. Pearson.
Pacione, M. 2001. Urban Geography A Global Perspective. Routledge.
Derudder, Ben and Taylor, Peter. 2016. Change in the World City Network, 2000-2012. The Professional Geographer. 68(4) pages 624-637
China’s urban system
Chang. S. 1963. The Historical Trend of Chinese Urbanization. AAAG. Vol 53 (2)
Wu F. 2016. Emerging Chinese Cities: Implications for Global Urban Studies. The Professional Geographer, 68(2), pages 338–348
Sheppard. E. 2016. Emerging Asias: Introduction The Professional Geographer, 68(2), pages 309–312

Watch our videos and review your learning with the Crash Course App!
Download here for Apple Devices:
Download here for Android Devices:

Crash Course is on Patreon! You can support us directly by signing up at

Thanks to the following patrons for their generous monthly contributions that help keep Crash Course free for everyone forever:
Dave Freeman, Hasan Jamal, DL Singfield, Lisa Owen, Jeremy Mysliwiec, Amelia Ryczek, Ken Davidian, Stephen Akuffo, Toni Miles, Erin Switzer, Steve Segreto, Michael M. Varughese, Kyle & Katherine Callahan, Laurel Stevens, Vincent, Michael Wang, Stacey Gillespie (Stacey J), Alexis B, Burt Humburg, Aziz Y, Shanta, DAVID MORTON HUDSON, Perry Joyce, Scott Harrison, Mark & Susan Billian, Junrong Eric Zhu, Rachel Creager, Breanna Bosso, Matt Curls, Tim Kwist, Jonathan Zbikowski, Jennifer Killen, Sarah & Nathan Catchings, team dorsey, Trevin Beattie, Divonne Holmes à Court, Eric Koslow, Jennifer, Dineen, Indika Siriwardena, Khaled El Shalakany, Jason Rostoker, Shawn Arnold, Siobhán, Ken Penttinen, Nathan Taylor, Les Aker, ClareG, Rizwan Kassim, Alex Hackman, Jirat, Katie Dean, Avi Yashchin, NileMatotle, Wai Jack Sin, Ian Dundore, Justin, Mark, Caleb Weeks

Want to find Crash Course elsewhere on the internet?
Facebook -
Twitter -
Tumblr -
Support Crash Course on Patreon:

CC Kids:

#CrashCourse #Geography #UrbanGeography

Whether it’s religion or agriculture or bananas, in human geography we love exploring diffusion, or the spread of ideas and innovations.

We want to know why something exists here and not there, and how it got there. Which is probably why we’ve kinda gone bananas for the Silk Roads in multiple episodes.

These trade routes at times passed goods and ideas all the way from Portugal to Tokyo. Which might make us wonder what happened to all the stops along the Silk Roads. Many of these hubs wielded tremendous power over their regions -- a legacy which in many places still continues today.

Take Guangzhou, which is an ancient Chinese city which European traders knew as Canton. Once a major part of the maritime portion of the Silk Roads, today its creative experimental architecture has almost completely replaced the old city. The population of the city and the surrounding urban area has skyrocketed from about 2 million in 1980 to nearly 13 million in 2022.  Which helps make Guangzhou and its ferocious economic activity part of one of the fastest growing urban regions in the world – the Pearl River Delta.

What’s happening in Guangzhou is part of a global phenomenon. We’re living in an increasingly urban world, and according to UN estimates people living in urban places outnumber those in rural areas -- which is actually new for most parts of the world.

I’m Alizé Carrère, and this is Crash Course Geography.

 Urban Geography (1:22)

Though I’ve already said it a bunch of times, the word urban is actually pretty hard to define in geography, because what counts as “urban” changes depending on what country or region you’re in. For instance some countries define it based on population numbers or population density.  But we could also use infrastructure development or the type of employment the people living there have.

Even still, studying urban places like towns and cities is important in many social sciences. In geography, we’re particularly interested in how urban places are related to each other as points in space and how they’re laid out internally.

We call this urban geography, which is a sub field of human geography that focuses on urban spaces. Urban geographers want to know why towns and cities are where they are, and why some cities are so much larger than others. We want to describe, understand, and explain the pattern of cities and the arrangement of different activities within them.
So we ask questions like what causes some cities to decline and some to grow rapidly? Why do some have suburbs and others are just one large city? How are cities planned and laid out and what are some of the environmental impacts of cities?  And how and why do cities become segregated by race or income? That’s a lot of questions! And this is why we at Crash Course are taking four episodes to talk about some of the basics of urban geography.

 Urbanization (2:36)

Which means we better clearly establish and define the space where all of this studying is taking place! We all know a city when we see one, but what are cities, really? Turns out, there’s no universal definition of one.

Historically, cities were differentiated from other forms of settlement by their larger population size and if the people living in them weren’t directly involved in agriculture. Cities were centers of political, economic and social power and were generally places with a high population density, or the number of people occupying an area of land.

Today we have many different places of many different sizes lumped under the word “city.” This includes places like Jakarta, a megacity with over 10 million people that dominates its national economy.  And when a city’s population grows to more than 20 million it’s called a metacity like Mumbai, Dhaka or Shanghai. And when multiple cities interconnect to form a dense urban corridor like the one that extends from Boston to Washington D. C., we have a megalopolis.

But regardless of how we define it, it’s the social function of the city – how central it is to so many human interactions and endeavors -- that’s key to its existence. Cities have developed as central points within various economic systems: like agrarian, merchant, industrial, and capitalist economies.

For instance, take China’s southern coastline where many protected bays suitable for harbors allowed for a series of ports to develop in the late 1970s when China adopted an open door policy. This encouraged foreign investment into the country and allowed more trade with the rest of the world. While no actual doors were opened, almost overnight tranquil rural areas were transformed into factories and apartment buildings and other urban land uses. The cities of the Pearl River Delta became part of Special Economic Zones and were designed to attract the foreign capital and technology to manufacture goods for export.

Take Guangzhou. As an export processing zone with plenty of cheap labor and land, national, regional and local governments have made enormous investments in transportation and communication infrastructure to make it competitive and more prominent in the global economy. So the open door policy, the industrialization of the Pearl River Delta, and the government investment all accelerated the region’s urbanization or the shift in residence of population from rural to urban areas.

 Why Urbanize? (4:40)

As urban geographers, we take skills from both physical and human geography, and a bunch of other fields, to study the way people and economies move between rural and urban living. So we care about urbanization for the same reasons we care about why people migrate: because it means a change to the structure of the human experience. And worldwide, urbanization is kinda on the rampage.

The UN estimates that by 2050 two thirds of the world’s population will be urbanized. And that's the inverse of how it was just a century ago when less than one-third lived in cities. China itself reflects this dramatic shift -- until the 1990s about 70 percent of China’s people still lived in the countryside.

Today this has (almost) flipped with 61 percent of people living in cities. China’s government has relaxed some of the residency laws that previously controlled where people could live and have also drawn up plans to establish hundreds of new cities for better or worse. They’re investing in cities as powerful engines of economic development that bring higher incomes and improved living standards that lead to a better quality of life for people.

But studying cities is vital for so many reasons. Cities are also a key part of economic development which is a specific form of economic growth that increases the complexity of an economy. Think of all the different jobs people do in any typical large and prosperous city, like New York, London, or Shanghai.  In rural areas the range of jobs is simpler.

In fact the urbanist Jane Jacobs -- who specialized in city planning which we’ll talk about more next time -- has argued that instead of thinking of economic development as something that happens to countries, it’s a process that happens in and through cities. Unlike countries which are defined by their borders, cities are economic entities geographically defined by their connections.

So for instance Shanghai, the foremost financial and trade center of China is as closely tied to another preeminent city like Singapore as it is to almost any other Chinese city. But urbanization isn’t just about the population growth of towns and cities. It also means other changes – like in the sectors of the economy people work in or in the makeup of the city’s population.  And as some cities decline, the relative size of an individual city, the role it plays, and its relationship to other cities also changes.

 Central Places (6:43)

It’s a dynamic landscape. So geographers think through the process of urban growth and change and the distributions and patterns of cities using urban systems, or the ways in which cities of different sizes are connected within a set of urban settlements.

Like many cities both old and new became central places for the surrounding rural areas. A central place is well, centrally located so that accessibility from surrounding areas is maximized.

For example, in the 1930s towns and cities in Southern Germany were still mostly used for local markets and shopping.  And this is when economic geographer Walter Christaller looked at consumer behavior to explain the size and distribution of settlements within an urban system. Called Central Place theory, Christaller -- and later another economist August Lösch -- wanted to explain why urban systems were arranged the way they were. And they propose d that economics were key.

Christaller explained that a large number of small settlements will be situated relatively close to one another because people don’t want to travel far for everyday needs, like getting bread from a bakery. But people would travel further for more expensive and infrequent purchases or specialized goods and services which would be located in larger settlements that are farther apart. But Christaller explained settlement patterns using an idealized region with uniform terrain, climate, and soils, where everyone could travel easily in all directions.

And a model like that doesn’t respond well as the world changes. Because today we can talk about a global urban system where global or world cities sit at the very top of the hierarchy, regardless of whether they’re centrally located or not. These leading cities like New York, London, and Tokyo are part of a network defined by their connections to each other.

 Hierarchy of Urban Areas (8:15)

And identifying networks of cities of different sizes and ranks is fundamental to understanding the evolution of the contemporary world. For instance, in countries with a high standard of living, we’ve noticed a different pattern based on population size within the overall hierarchy of urban systems. The rank size distribution basically says that if settlements are ranked from largest to smallest by population, then the population of, say, the second largest city will be one half the size of the largest and the third largest will be one third, and the fourth largest will be a quarter the size, and so on.

But in many parts of the world, the rank size rule becomes distorted when the population of the largest city is wildly large, especially when compared with the next largest city. Like in 2022 Buenos Aires is 10 times larger than Córdoba, the second largest city in Argentina. Geographers call this primacy, and primate cities like Buenos Aires can also account for such a huge share of the economic, political and cultural activity they dominate within their urban systems.

So the rule doesn’t hold in all cases. But it’s still valuable to learn about and build on these models as we try to understand cities and how they grow. And there are many other models and factors that help us understand urban systems.

Like most primate cities are found in low and middle-income countries where many of them were colonial cities at some point in their histories. And being a colonial city has likely contributed to the dramatic influence many primate cities have on their regions because of the key roles they played in the economy under colonialism. For example, many primate cities were ports through which European powers extracted raw materials from the rest of the region, and places like Buenos Aires grew based on dealing in things like wool and cereals.

 Summary (9:47)

So there are many ways to explain urbanization and how different urban systems are structured, from economic theories like Central Place theory to the lingering influences of colonialism. Ultimately, economies shifting around the world to be more focused on technology, industrialization land services means that city growth and urbanization have become irreversible.

Urbanization is one of the most important and prolific geographic phenomena in today’s world, which means what we’ve covered so far is just the tip of the iceberg.  Most of the world lives in an urban area, and how that happened requires us to look at both global forces and local factors, which we’ll do more next time when we take a peek inside a city.

Many maps and borders represent modern geopolitical divisions that have often been decided without the consultation, permission, or recognition of the land's original inhabitants. Many geographical place names also don't reflect the Indigenous or Aboriginal peoples languages.

So we at Crash Course want to acknowledge these peoples’ traditional and ongoing relationship with that land and all the physical and human geographical elements of it. We encourage you to learn about the history of the place you call home through resources like and by engaging with your local Indigenous and Aboriginal nations through the websites and resources they provide.

Thanks for watching this episode of Crash Course Geography which is filmed at the Team Sandoval Pierce Studio and was made with the help of all these nice people.  If you want to help keep all Crash Course free for everyone, forever, you can join our community on Patreon.