Hey everyone, welcome back to My Weird Prompts! I am Corn, and I am feeling especially crowded today. I was just trying to find a quiet corner in the kitchen this morning to make some coffee, and it felt like a tactical maneuver. I had to dodge a stack of cookbooks, navigate around the dishwasher, and somehow find a square inch of counter space that was not occupied by a toaster or a stray bag of flour. It is funny how even in a house with plenty of rooms, we all seem to gravitate toward the same four square feet of kitchen at seven in the morning.
Herman Poppleberry here. And yes, the house is definitely feeling full lately. But it is perfect timing because our housemate Daniel sent us a prompt that explores exactly why we do this to ourselves. He was telling us that his wife, who is an architect and very passionate about urbanism, was thinking about this on her way to Ikea. She was stuck in that classic Saturday morning traffic and was curious about the very first big cities and why humans choose to cluster together in these dense urban areas even when there is technically plenty of open space out there. I mean, you look at the Negev desert or the Galilee, and there is space. But here we are, fighting for a parking spot in Jerusalem.
It is a great question. You look at a map of the world and there are massive stretches of land where nobody lives. We could all have our own little kingdom with a moat and a garden, but instead, we choose to live on top of each other in places like Jerusalem or New York or Tokyo. Daniel was also asking about the natural limits to this. Can urbanization go too far? And where does vertical farming fit in? Can we actually grow enough food in a skyscraper to support a city of millions, or are we just building very expensive salad bars?
I love this because it touches on history, economics, and biology. If you look back at the timeline of humanity, we spent the vast majority of our history as nomadic hunter-gatherers. For roughly two hundred thousand years, we were spread out by necessity because the land could only support a few people per square mile. But then, the Neolithic Revolution happens around ten thousand years ago, and everything changes. We stop chasing the food and start making the food stay put.
Right, agriculture. Once you can stay in one place and grow a surplus of food, you do not need everyone to be a food producer. You can have specialists. You can have the first bakers, the first blacksmiths, and eventually, the first architects like Daniel’s wife. But where did the first real big city actually show up? Because a village of a hundred people is not exactly a metropolis.
Well, it depends on how you define a big city. If you are looking for the absolute first urban center that truly functioned like a city, many historians point to Uruk in ancient Mesopotamia, which is modern day Iraq. Around four thousand BCE, Uruk was massive for its time. Around twenty-nine hundred BCE, it had a population estimated between forty thousand and eighty thousand people. To us today, that is a small town, but in four thousand BCE, that was like finding a spaceship in the middle of the desert. It was a complete anomaly.
Forty thousand people around 2900 BCE is incredible. I imagine the logistics of just getting water to that many people without modern plumbing must have been a nightmare. But they did it. Today, it's often called the Venice in the desert because of its incredible canal system. They did not just have a well; they had a sophisticated network of waterways that brought the Euphrates river right into the heart of the city for transport and irrigation.
Exactly. And that infrastructure is what allowed them to grow. They built these massive monumental structures from mud bricks, like the Eanna district dedicated to the goddess Inanna. But here is the cool part: because they had so many people and so much trade, they needed a way to keep track of it all. That is where we see the birth of writing. Cuneiform did not start with poetry; it started with accounting. It was a way to record how many sheep or bags of grain were moving through the city gates. Urbanization literally forced us to invent the written word because our brains could no longer keep track of everyone in the tribe.
So the city created the need for data. That feels very modern. However, Uruk was not the first to reach that magical one million mark that we associate with a true metropolis today. That is a whole different level of complexity.
No, that honor almost certainly belongs to Rome. Around the early Empire in the first century CE, Rome became the first city in history to top one million inhabitants. It was the only city to hold that title for centuries. Think about the sheer engineering required for that. They had eleven major aqueducts bringing in millions of gallons of fresh water every day. They had the Annona, which was a state-organized grain dole to feed the urban poor. They even had high-rise apartments called insulae that were sometimes six or seven stories tall.
I bet those insulae were a bit of a nightmare to live in. No elevators, and I imagine the fire risk was through the roof. But it shows that the desire to be at the center of power and culture was so strong that people were willing to live in cramped, dangerous conditions just to be in Rome.
And what is really staggering is the gap that followed. After the fall of Rome, the city’s population plummeted. We did not see another city hit a million until London did it around 1811. Think about that gap! For almost two thousand years, the world did not have a single city as big as ancient Rome. It shows that urbanization is not just a steady upward line. It can retreat. It requires massive infrastructure, political stability, and a reliable food supply to maintain that kind of density.
That is a staggering thought. It really highlights that cities are fragile ecosystems. But let us get into the why. Why did people want to be in Rome or Uruk? Daniel mentioned this idea of niche interests. In a small village, if you play a very specific, weird instrument, you are probably the only one. You are the weirdo with the lute. But in a city of a million, you can find a whole orchestra of people who play that same weird instrument.
Exactly. Economists call this agglomeration economies. It is the idea that there are massive benefits to being close to other people and firms. Alfred Marshall, a famous economist, talked about three main pillars of this. First, labor pooling. If you are a specialized worker, you go to the city because that is where the jobs are. If you are a business, you go to the city because that is where the talent is. Second, input sharing. You can have specialized suppliers that only exist because there are enough customers to support them. Like that shop that only sells left-handed scissors Daniel mentioned.
And the third pillar?
Knowledge spillovers. This is my favorite. It is the idea that ideas literally jump from one person to another because they are grabbing coffee at the same place or bumping into each other on the sidewalk. In Silicon Valley or the tech hubs here in Israel, you have people from different companies talking shop at a bar, and suddenly a new startup is born. Proximity breeds innovation. You cannot get that same level of spontaneous friction on a Zoom call.
It is the power of the crowd. But it is not just about economics. There is a psychological element too. Even though we complain about the noise and the crowds, humans are fundamentally social creatures. We evolved in small tribes, and cities are like a hyper-charged version of that tribe. But as Daniel’s wife mentioned, the design matters. She is big on walkability. And that is where the friction starts, right? We want the benefits of the city, but we do not always love the way cities are built, especially when they are designed for cars instead of people.
Oh, do not get me started on the car-centric design. We have talked about this in past episodes. If a city is built for cars, you lose that spontaneous interaction. You are in a metal box moving from point A to point B. You are isolated. But if a city is walkable, like parts of Jerusalem or Paris or Tokyo, the city itself becomes your living room. You are constantly bumping into the world. That is where the magic happens. But that magic is getting expensive.
It really is. Daniel mentioned some of the downsides he feels living here in Jerusalem. The incessant honking of cars, the never-ending roadworks, and the rental market. I mean, we have all felt that. The housing market in major cities is becoming a massive barrier. It is almost like cities are becoming victims of their own success. Everyone wants to be there for the opportunities, which drives the price of a shoebox apartment up to five thousand dollars a month in places like New York or London.
It is a real problem. And it leads to the question of natural limits. Can a city just keep growing forever? Some people think vertical farming is the answer to the food limit. If we can grow our calories in the same building where we live, we do not need the rural countryside as much, right? Well, the research is actually quite sobering.
Yeah, I was looking into the energy requirements for vertical farming. It turns out that growing leafy greens like lettuce or spinach is one thing because they are mostly water and do not require a ton of light energy to produce calories. In fact, for leafy greens, an optimized vertical farm typically uses about ten to fifty kilowatt-hours per kilogram. That is a lot, but for a high-value crop, it can work. But if you want to grow staple crops like wheat, rice, or corn indoors, the numbers get scary.
It is what researchers call the agricultural wall. Nature provides the sun for free. To replace the sun with LED lights and climate control inside a skyscraper requires a massive amount of energy. One study showed that the electricity cost alone to grow wheat in a vertical farm is about ten times higher than the total market price of wheat grown in a field. Even with advances in renewables, we are nowhere near making indoor staple crops economically viable. So, for the foreseeable future, every city is still tethered to a massive amount of rural land.
So the limit is not just how many people you can fit in a tower, it is the energy and land required to feed them. You might live in a dense urban core, but you are being kept alive by thousands of acres of flat, open farmland hundreds of miles away. And there is another limit we should talk about: the psychological limit. We mentioned in past episodes that productivity is high in cities, but so is stress.
That is a great point. Urban psychology is a massive field now because we are realizing that human brains were not exactly designed for the sensory overload of a place like Tokyo or New York. There was a fascinating study out of South Korea recently about the urban paradox. They found that city dwellers often have higher rates of depressive symptoms despite having much better access to mental health services than people in rural areas. The constant startle response from sirens, the lack of green space, and the social isolation of being in a crowd of strangers can lead to higher rates of anxiety and mood disorders.
It is like we are over-stimulated and under-connected at the same time. We are surrounded by millions of people, but we do not know our neighbors. One research paper from late twenty twenty-five suggested that urban living in the Global North is linked to a significantly higher risk for mental disorders like schizophrenia compared to rural living. It seems our brains have a hard time processing the sheer density of social information in a metropolis.
So the natural limit might not be a lack of food, but a lack of mental well-being. We might reach a point where people just say, I cannot do this anymore, and we see a reverse migration. We are already seeing a bit of that with the rise of remote work. People are realizing they can have the niche interests via the internet but live in a place where they can actually hear the birds. But then they miss the physical proximity. It is a paradox. You want the quiet, but you also want the five different types of artisanal sourdough within walking distance.
It is the ultimate trade-off. And I think that is why the work Daniel’s wife does as an architect is so critical. We have to figure out how to make high-density living feel human. How do you buffer the noise? How do you integrate nature into the verticality? There are some cool projects in Singapore and Milan where they are literally wrapping skyscrapers in trees to create vertical forests. It helps with the urban heat island effect and gives people that psychological connection to nature.
If we can solve those habitability issues, cities can continue to be the engines of human progress. If we do not, they might just become very expensive stress chambers. I like that term, stress chambers. It definitely feels like that when the construction starts at six in the morning right outside your window.
But even with the noise, I do not think I could give up the energy of the city. There is a pulse to it that you just do not get in the suburbs. It is that feeling that something important is happening just around the corner. Whether it is a new art gallery opening or a breakthrough in a research lab, cities are where the future is being written. We cluster because we want to be part of that story.
Exactly. It is the visibility of progress. When you see thousands of people moving and working and creating, it gives you a sense of being part of something larger than yourself. That is a powerful human need. It is probably why we started building cities like Uruk and Rome in the first place. We wanted to be where the action was, even if it meant living in a six-story walk-up with no plumbing.
So, to summarize for Daniel and his wife, the first big city was Uruk, which was a marvel of canal engineering and the birthplace of writing. But Rome was the first to hit the one million mark, supported by aqueducts and a massive grain supply. We cluster because of the economic and social power of the crowd, the niche communities, and the shared resources. But the limits are real. They are tied to energy, the cost of food, and our own mental health.
And vertical farming is a great tool for fresh greens and urban resilience, but it is not going to replace the vast wheat fields of the world anytime soon. We are still a species that depends on the sun and the soil, no matter how many LEDs we plug in. If you are living in a city, you have to find your own ways to manage the downsides. Whether that is good noise-canceling headphones or finding that one hidden park that nobody else knows about. It is all about balance.
Well, I think that covers a lot of ground. Daniel, thanks for sending that one in. Give our best to your wife, she definitely picked a topic that gets us fired up. It makes me want to go out and appreciate the chaos of Jerusalem a little bit more today.
Definitely. And hey, if you are listening and enjoying these deep dives, please take a second to leave us a review on your podcast app or on Spotify. It really does help other curious people find the show. We love hearing your prompts, so keep them coming.
It really does. You can find all our past episodes and a way to get in touch with us at our website, myweirdprompts.com. We are also on Spotify, so make sure to subscribe there for all the latest updates. We have some great topics coming up in the next few weeks.
This has been My Weird Prompts. Thanks for hanging out with us in our crowded little corner of Jerusalem. We appreciate you spending your time with us.
Until next time, stay curious and maybe go for a walk in a park if you can find one. It is good for your brain! Goodbye!
Goodbye everyone!
