Why would a modern city built on flat land in a relatively large country have little to no urban sprawl?

Question

I am making an RPG and am using this image (source: https://www.pixiv.net/en/artworks/58916801) as inspiration for a large city.

This city:

• Is located in a country roughly the size of Panama
• Has some flat land to expand onto near it
• Stops abruptly and descends into wilderness
• Is entirely covered in skyscrapers up until its end

Why would a city be entirely comprised of skyscrapers but stop abruptly without suburbs? I know that the city could not expand into the waterfall, but there appears to be some flat land near it that it can expand to (in the background). That land is not used, not even for agriculture. How could this happen? Are there any real life examples of cities like this?

Assuming that the city is inhabited by humans and has the same physics and geology as Earth (ignore the mountains in the background).

To confirm: The planet is at a present day tech level. Computers, airplanes, and cell phones are commonplace throughout the world.

Answer 1

Looking at your picture, the obvious answer is that this is all parkland: the impressive chasm with waterfalls in the middle of the picture is a famous scenic location, and the surrounding area has been reserved for recreation and nature conservation.

The urban sprawl, such as there is of it, is on the other side of the city behind the skyscrapers. And possibly surrounding the park on other sides, if the city has expanded there too. Either way, it's not visible in the picture, perhaps deliberately so by careful choice of vantage point. (See also: countless nature photos and videos that look like they've been taken in untouched wilderness, even though there's actually roads and buildings and power lines etc. just outside the frame.)

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But that's kind of a boring answer from a worldbuilding viewpoint. (Although I can certainly see ways to take it and run with it — for example, maybe most of the world is monotonous high-efficiency farmland, with a few of these carefully maintained "natural" parks sitting side by side with densely packed cities whose inhabitants can enjoy them and pretend they're living in harmony with nature.) So let me suggest a few more possibilities.

For example, maybe the picture is taken during the dry season, and all that green "grassland" around the chasm is actually part of the channel of a wide river that the city is built next to. When the rainy season comes, it'll all be submerged in the shallow but rapidly flowing river. The patches of woodland dotting the plain are actually low-lying (and possibly somewhat shifting) islands that are hardly safer to build on that the riverbed itself.

That kind of geography is actually quite characteristic of the upstream side of very large curtain-type waterfalls (like the Victoria Falls in Africa or the Iguazu Falls in South America), as they typically form in places where a major river flows over a flat bed of hard basalt until plunging off the slowly eroding edge into a deep chasm cut into softer rock beneath. Add sufficient seasonal variability in rainfall, and you could easily get a landscape much like depicted in your image (plus or minus the city).

(As noted in the comments to SRM's answer, floodplains are often used as farmland, as the flooding tends to spreads sediments that act as natural fertilizer. However, for this to be practical, the land needs to be dry for long enough for crops to grow — if it's underwater for most of the year and only briefly dry, farming becomes a lot harder. Also, even if the land was indeed used for early low-tech farming — which could explain why the city was originally built there — the farms might've moved elsewhere after the invention of artificial irrigation and new farming techniques better suited for places where the water supply can be controlled and where there's less risk of your crops and your boundary markers getting washed away by unseasonal rains.)

Again, there could easily be suburbs on the other side of the city, or "behind the camera" on the other side of the river. Or maybe not, depending on the economics of the city, zoning laws and local culture. (Maybe the city actually lives almost entirely off tourism, and those tall buildings are in fact all hotels with a nice view of the waterfalls?)

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Another possibility that occurs to me is that the flat green areas could actually be pastureland. Probably, given that those grassy areas seem to extend quite far down the chasm, for sheep or goats or some other local grazing animals that don't mind a bit of climbing. After all, clearly something is keeping that land from getting covered in trees and bushes, and if it's not seasonal flooding or diligent park staff with lawnmowers, the most likely third option is that it's being grazed.

So why would the city be surrounded by a giant pasture, instead of the usual suburbs and farms? Maybe the people who built the city never really developed agriculture (if you hadn't specified that they're human, I'd be tempted to suggest that they might be a species of obligate carnivores), and thus also never acquired a cultural preference for single-family homes with private gardens. Instead, their society is (or at least has traditionally been) divided into a (dwindling) nomadic caste that travels with the herds and has no fixed abode, and a (growing) sedentary caste of crafters and traders and other sorts of cityfolk who live in dense communal settlements and subsist off the food produced by the herdspeople, traded for manufactured goods and services.

(Or perhaps they all live in the cities for most of the year and let most of their livestock roam free, only gathering them up once or twice a year for counting and culling, much like arctic reindeer herders still do in the real world. The herds might be communally owned, perhaps with each town having shared ownership of all of its semi-domesticated livestock, since having too many separate owners in the same area could tend to make separating the herds at counting time too cumbersome.)

If you do decide to go this route, it's worth noting that herding animals, while less labor-intensive than agriculture, is also considerably less productive for a given area of land. Traditionally, in the real world, large scale herding has only been common in places where either population density is low — often on the periphery of farmland, which itself surrounds towns — or where the land is for some reason not well suited for any available farming methods. If you want a large city to be supported (almost) entirely by herding, that's going to require a lot of pastureland, and you're not likely to have another similarly sized city anywhere nearby. (Unless maybe there are also coastal towns and cities supported by fishing…)

Answer 2

Flood plain

The flat land is just enough lower down that when the river flash floods, as it does in just about any rain, that land becomes a raging torrent. This is a pretty common reason for cities to avoid a place of land.

Answer 3

• Some person/company owns the land and refuses to sell.
• The land is designated as a national park. The city grew right to the edge but not one step further. Think Central Park in NY, even if that is no nature preserve.
• The surrounding land is actually another country, e.g. Hong Kong before it went back to China.

Answer 4

Because everything they need is available within those skyscraper.
BTW, you call it skyscraper, they prefer the term arcology.

Arcology, a portmanteau of "architecture" and "ecology",[2] is a field of creating architectural design principles for very densely populated, ecologically low-impact human habitats.

The term was coined in 1969 by architect Paolo Soleri, who believed that a completed arcology would provide space for a variety of residential, commercial, and agricultural facilities while minimizing individual human environmental impact.

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An arcology is distinguished from a merely large building in that it is designed to lessen the impact of human habitation on any given ecosystem. It could be self-sustainable, employing all or most of its own available resources for a comfortable life: power; climate control; food production; air and water conservation and purification; sewage treatment; etc. An arcology is designed to make it possible to supply those items for a large population. An arcology would supply and maintain its own municipal or urban infrastructures in order to operate and connect with other urban environments apart from its own.

When they finish the propulsion part (a specialized application of their own fusion reactor) and the "Space Research and Colonisation Agency" greenlights it, some of them take the flight to space and transform themselves in a generation ship.

Bonus: if the city is around a space elevator, the "launch generation ships into space" can become the main purpose for the city existence and reinforce the idea of "don't rely on anything from environment except the materials you need for building arcologies. You will need to be self-suficient".
Such a building may take 2 or more generations from start to finish, so the actual travelers will be completely adjusted to the conditions of the trip.

Answer 5

Urban sprawl is the result of a tradeoff: people are willing to spend longer travelling and be further (on average) from places they need to visit, in order to have more space to themselves. This is largely a matter of societal preference, coupled with historical precedent (humans were able to spread outwards before they could spread upwards).

So, your world just has to be one where people value their time more than they value their space. This does not necessarily need any particular explanation; it's simply a society with different preferences to the one we are familiar with. However, if you do want a specific reason: your society has not developed (or has banned, or chosen not to use...) mechanised transport. If everything you do has to be within easy walking distance, there is a strong incentive to spread upwards.

Answer 6

Consider the real-world example of Shibam Haḍramawt, also known as "the oldest skyscraper city in the world". Most of these tower blocks were built in the 16th century and are 5 to 11 stories tall.

The design was strategic; the walls protected residents from flooding during the rainy season while maintaining proximity to its primary source of water. Additionally the fortifications repelled nomadic raiding parties, while the buildings offered a high vantage point from which to see them approaching.

It's possible that both of these threaten your city, particularly the flooding, given the many rivers close-by.

The urban density also shades buildings for most of the day, though this may not apply to your setting depending on the climate.

Answer 7

You don't need magic. You just need good zoning. The inhabitants prefer a compact city surrounded by wilderness instead of a downtown surrounded by kilometers of suburbs. Therefore, building is only allowed in the city area and building regulations are adjusted there to allow buildings high enough to comfortably host the whole population and the facilities required by their economy without ruining the environment.

However, if you don't want high tech food producing, there must be agriculture somewhere. The fields may be on the other side of the city or they could be some light brownish patches in the background of the image.

Answer 8

An additional idea that could work together with some of the other answers: Transportation in your world is so expensive (oil prices etc) that cities tend to be compact to ensure short commuting distances. This would apply to all cities in your world though, unless you could impose something like an oil embargo on your country. The area is not used for agriculture because arcology is used instead.

The advantage of this reasoning is that you don't need a very strong reason to make city expansion impossible but just undesirable, as obstacles like unstable terrain could be removed. Money is a strong force!

Answer 9

The planet has a problem with werewolves. The city fathers consulted a mathematician who explained because of the isoperimetric inequality a circular wall would have the greatest area for a particular length of wall. Of course all the residents want to live inside the wall where they are protected.

Answer 10

Perhaps the land is riddled with mines or caves or other subterranean structures that make it highly unstable and likely to collapse. This is known by the authorities and they will not permit any building to take place on it.

Another possibility: the land is stable but contaminated with asbestos, radioactive materials, chemicals or high levels of naturally occurring poisonous minerals below the surface and the authorities do not want the soil disturbed.

Although the surface looks and feels solid enough to walk on it is actually a very ancient and deep lake. Vegetation has grown across the surface and has formed a dense mat. This mat has become the basis for more vegetation and even small trees in places as old material rots from below it is replaced by new material sinking down from the surface. So the area looks like a park but can't be built on because its not solid enough.

Answer 11

There was a recent plague which killed 50% of the population. They had expanded somewhat into the countryside, but with the loss of population it's cheaper to just expand into the city. The wilderness has assorted magical creatures and threats in it that make it very expensive and difficult to expand into.

Does this happen in real life?

Generally not. Rivers that flood make for great farmlands, and natural places have great resources. Greed normally makes people expand. You would need different incentives to make people stay in the city.

Answer 12

There are pretty good answers so ill try exploring alternatives.
Is this a high magic world? There could be a magical bubble around the city that provides some sort of benefit to staying inside of it such as better health, defense, or longevity.
Defense can mean both from invaders but also perhaps the world has a relatively strong background radiation or a thin atmospheric layer that doesn't filter solar radiation well. One could travel outside the bubble, even spend months out without much health risk, but living out there would be detrimental to ones health over long periods of time.

Is the world technological? constant solar flares disrupt electrical devices and the city bubble(possibly a physical dome, a field generator or strange mineral deposits in the earth in the area) is the only practical protection against the effects. Not enough people are willing to give up electricity/radio/the internet to have any sort of sizable settlement outside the city

Answer 13

Started with extortive property taxes based on land occupied.

As higher and higher buildings become a tradition, owning a high place became a sign of wealth and the social ladder mirrored in the buildings. The growing economy and the demand of high flats just stimulated the developers to build higher and higher.

Answer 14

Predators roam the land. Hidden predators. INVISIBLE predators! HIDEOUSLY UGLY invisible predators, who only become visible to those they are about to eat, who connect telepathically with their chosen prey and who plant terrifying subliminal messages ("I'M GOING TO EAT YOU!") in their minds! Oh, gods, the horror!!! Is there no hope?!?!?

ONLY LITTLE RED RIDING HOOD CAN SAVE US!!!!!!

Answer 15

Kowloon Walled City was a densely-populated, ungoverned enclave in Hong Kong. The exact details on how it acquired this unusual legal status you can find elsewhere - suffice to say, there were different legal regimes on either side of the wall providing a combination of demand and ability to pack more in there.

To use a more contemporary example, think of casinos built on tribal land in the United States. Or Vinod Khosla's attempt to make a beach private under the Treaty of Guadalupe Hidalgo, had it been successful.

If you need to explain why they don't simply change the law to let the city grow, you could have the treaty that created the unusual legal status also be the source of the source of the current governments' legitimacy. Or of course have the other side of the wall be another country that isn't happy to cooperate!

Of course, given that your image shows someone travelling by horse, and no other transport, perhaps nobody knows how to build skyscrapers but there's enough room nobody wants to build anything more. Maybe the existing city was teleported, fully built, from another planet or dimension. Buildings that straddled the teleporting boundary have long since fallen down, leaving a perfectly spherical chunk of downtown Tokyo from the year 2101.

Answer 16

You civilization simply has a different philosophical view on land usage and the exploitation of natural resources than civilizations that have been traditionally dominant on real life Earth. "We" embrace the notion that "civilization" and "wilderness" are diametrically opposed, and that everything is one or the other. Your civilization sees humanity and all its works as an integral part of nature, and seeks at all times to live harmoniously with its surroundings. Your civilization puts so much value on the natural splendor of the landscape that very few members of it would even come up with the idea to destroy it to build something, and most would be horrified at the suggestion. People who voice such suggestions might be considered dangerously deranged and incarcerated in mental institutions.

It's fairly simple to see how real life people might use religion to justify "our" consumption practices, especially the translations of Genesis that have God give "dominion over the earth" to humanity. So in your world, the dominant religion(s) stress humanity's custodial role, and perhaps encourage humanity to make an Eden of the Earth. Tie the afterlife to the health and well-being of the planet, rather than an escape to a separate "heaven." You might have an ecumenical crisis when people begin to figure out that their sun is eventually going to go out/expand enough to consume the planet, but the ideas and perspectives of the religion will be considered "human nature" by that point, even if the faith itself dies.

It's also worth noting that any society that embraces rampant consumption and exploitation will probably have an significant technological advantage over societies that don't. That's pretty much what happened in real life. Many (if not most) of the cultures native to the Americas (and not a few African and Pacific cultures) held a general belief of a kinship with nature. By the early 1500s, no American culture had developed bronze, putting them at least 4,500 years behind "everyone else" in metallurgy (and North America was even farther behind, with no evidence of local smelting until after colonization had started). It will probably take your society much longer to get to a "modern" level, which lets you make your society as ancient as you want.

Answer 17

To try a different idea: what if this city did not grow "organically"? Perhaps it was built very rapidly, by a small group of people. Perhaps it is not even well populated yet, like China's supposed ghost cities.

So, the government (or even a large corporation) decides it needs a large number of people living in a small area, so it decides to build a city - and it has some way of feeding them that doesn't require cutting down the nearby vegetation and using it for agriculture.

One last possibility in this picture is that there is actually a country border on that river, and it would be illegal to settle across it.

Answer 18

Consider cultural or religious significance preventing it. If building there is culturally taboo it just wont happen.

Answer 19

The civilization may have an exotic construction method which requires some energy, only available locally, to keep the skyscrapers or even smaller buildings intact. Thus, they can build extensively where the energy source is, but have no technology for building outside that area.