Daniel sent us a prompt that's basically two things folded into one — first, what are the actual benchmarks for green space in cities, the kind of data you can point to when you want to argue that a municipality is failing its residents. And second, does an app exist for finding these spaces, or should someone build one? The deeper question underneath all of it is whether urban planning can deliberately engineer calm rather than just hoping it happens by accident.
I love that he framed it around that tension — country versus city, the feeling of being surrounded by green fields and cows and starting to go a bit stir-crazy, then craving the city again. That oscillation is real, and it's not just personal preference. There's a whole body of research on what makes urban environments restorative versus draining. By the way, today's episode is powered by DeepSeek V four Pro, which feels appropriate for a topic that's about precision and measurement.
DeepSeek writing a script about urban planning benchmarks. I suppose if an AI's going to weigh in on green space per capita, it might as well be one that can handle numbers. Alright, let's start with the data question, because Daniel was explicit — he wants to know if there's an established baseline, a number below which you're just creating unnecessary stress. And I think that's smart. Before you go criticizing Jerusalem or anywhere else, you want the benchmark.
The baseline that gets cited most often comes from the World Health Organization. They recommend a minimum of nine square meters of green space per person in urban areas. And that's a minimum — they also suggest that ideally you'd want people to have access to some form of green space within a fifteen-minute walk of their home. The nine square meters figure has been around for a while, but it's become the go-to international standard.
Nine square meters per person. what, about the size of a small bedroom?
And here's the thing — a lot of cities don't meet it. When you look at the data, dense older cities in particular struggle. Barcelona, famously, has something like six or seven square meters per capita in many districts. Paris was at around ten or eleven after some recent expansions, but historically it was much lower. And these are cities that people think of as having great public spaces.
The WHO number is the floor, but I'm guessing there's nuance about what counts as green space and how it's distributed.
That's exactly where the interesting stuff is. Because you could have a city that technically hits the nine square meters target by having one enormous park on its edge, but if most residents can't walk to it in fifteen minutes, you haven't really solved the problem. There's a researcher named Timothy Beatley who's been pushing this concept of biophilic cities for years — he's at the University of Virginia, runs the Biophilic Cities Network. His argument is that green space isn't just about total acreage, it's about integrating nature into the daily experience of being in the city.
Biophilic — literally "love of living things." I've come across the term. It's not just parks, right? It's street trees, green walls, rooftop gardens, daylighting buried streams.
Beatley's framework says a biophilic city does a bunch of things simultaneously. It preserves natural land within and around the city. It designs buildings that incorporate vegetation — not as decoration, but as integral to the structure. It makes sure there are quiet places where you can actually hear birdsong instead of traffic. And it connects all these spaces so wildlife can move through the city. Singapore is the poster child — they've got something like forty percent green cover despite being one of the densest places on Earth.
Singapore's interesting because they didn't stumble into that. It was deliberate policy starting decades ago. Lee Kuan Yew apparently had a personal obsession with greenery and cleanliness, and it became a national priority. So you've got buildings with entire forests growing up their sides, and park connectors threading through the whole island.
They measure it. Singapore tracks something called the Green Plot Ratio, which is basically the amount of leaf area relative to the site area. It's a much more sophisticated metric than just "how many square meters of park per person." A lawn and a multi-layered forest might both count as green space in a crude tally, but they're doing radically different things for biodiversity, for cooling, for psychological restoration.
Which brings us back to Jerusalem. Daniel mentioned the light rail, the high-rises, the sense that the municipality is paving over everything. What's Jerusalem's actual green space situation?
Jerusalem has some genuinely significant green assets. Sacher Park is about sixty acres right near the government quarter — it's the biggest public park in the city center. The Gazelle Valley, which was almost turned into housing but got saved by activist pressure, is now a sixty-plus-acre urban nature reserve with a wild herd of gazelles living in it. That's unusual — you don't find many cities that have a functioning ecosystem with large mammals right in the middle of things.
Gazelle Valley is one of those places Daniel was talking about — the lesser-known spots. Most tourists never hear about it. You go there and you're in the middle of Jerusalem but it feels like the Judean hills.
That's the paradox of Jerusalem's green space. On paper, the numbers might not look terrible because you've got the Jerusalem Forest on the western edge, you've got these big signature parks. But the distribution is uneven. The ultra-orthodox neighborhoods, for example, tend to have much less accessible green space per capita, partly because of density and partly because planning priorities were different when those areas were built. And the new high-rise developments Daniel's talking about — the ones going up along the light rail routes — those are creating very dense residential clusters, and the question is whether the green space is keeping pace.
Which is Daniel's core complaint, I think. It's not that Jerusalem has no parks. It's that the current development model seems to be maximizing built density without proportional investment in the spaces between buildings.
There's research backing up why that matters. A study out of the University of Exeter a few years ago — this was a longitudinal study following thousands of people over time — found that moving to a greener urban area was associated with sustained improvements in mental health. Not a short-term bump, but something that persisted for years. Another study from the Netherlands looked at health records and found that people living within a kilometer of green space had lower rates of anxiety and depression, even after controlling for income and other factors.
The causality question is always tricky with these studies — are happier people moving to greener neighborhoods, or do green neighborhoods make people happier? But the Exeter study tracking people over time helps with that. If you follow the same individuals and their mental health improves after they move to a greener area, that's stronger evidence.
And the mechanisms are fairly well-established at this point. Green space reduces ambient temperature — the urban heat island effect is real, and tree canopy can drop local temperatures by several degrees. It filters air pollution. It dampens noise, which is a huge and underappreciated stressor. And then there's the psychological dimension: the attention restoration theory developed by Rachel and Stephen Kaplan at the University of Michigan.
That's the one about soft fascination, right? The idea that natural settings engage your attention in a way that doesn't require effort, allowing your directed attention to recover.
Directed attention is what you use to do your job, navigate traffic, ignore distractions. Soft fascination is what happens when you're looking at leaves moving in the wind or water flowing — your attention is held, but without effort. That allows your cognitive resources to replenish. Urban environments, by contrast, demand constant directed attention — you're monitoring for threats, navigating crowds, processing signage. It's cognitively expensive.
When you're in the Irish countryside and all you see is green fields and the odd cow, your brain is in soft-fascination mode. But after a while, as Daniel said, you start going stir-crazy — that's your brain craving the stimulation of a more complex environment. The ideal seems to be having both available and being able to move between them.
Which is why the fifteen-minute access standard matters so much. If getting to green space requires planning a whole day trip, you're not going to do it on a Tuesday evening when you're stressed. But if there's a small park or a well-planted street or a community garden within a few blocks, you can get micro-doses of restoration regularly.
Let's get concrete about metrics. Daniel asked what a decent level of green space is per square kilometer or per resident. The WHO says nine square meters per capita minimum. What else is out there?
There's a few different frameworks. The European Union has something called the Green City Index, which looks at green space per capita but also at things like the share of the population living within three hundred meters of green space. Some German cities have adopted a standard of six square meters per person within walking distance, with larger regional parks serving as a second tier. The key insight from the research is that proximity matters at least as much as total quantity.
What about the concept of green belts? Daniel mentioned those specifically.
Green belts are a different beast. A green belt isn't necessarily recreational green space — it's a planning tool designed to contain urban sprawl by designating a ring of land around a city where development is restricted. London's green belt is the classic example, established in the nineteen-fifties. It covers something like five hundred thousand hectares. But green belts are controversial among urbanists because they can drive up housing costs by constraining supply, and they don't necessarily provide accessible recreation — a lot of London's green belt is private farmland.
A green belt might boost a city's green-space-per-capita number on paper without actually giving residents anywhere to sit on a bench.
And that's where we get into the distinction between "green space" as a statistical category and "usable green space" that actually delivers the restoration benefits. A highway median with grass on it is technically green space. It's not doing anything for your mental health.
Alright, so if I'm an urban planner and I want to engineer a city that's restorative, what's my checklist? I need green space within a fifteen-minute walk of every resident. I need it to be actual usable space — places you can sit, walk, hear something other than traffic. I need variety: small pocket parks for daily use, larger district parks for weekends, and some kind of wilder natural area accessible within a reasonable distance. I need tree canopy on streets, not just parks. And I need all of this to be distributed equitably across neighborhoods, not concentrated in the wealthy ones.
That's a solid summary. And I'd add: you need to think about the journey to the green space, not just the destination. A street lined with trees that leads to a park is doing restorative work the whole way. Beatley talks about this — the idea that the entire urban fabric should be biophilic, not just the designated green patches. Sidewalk plantings, green walls on buildings, daylighted streams, community gardens, even bird boxes and bat houses.
There's a project in Seoul that I think about a lot — the Cheonggyecheon stream restoration. They took a buried urban waterway that had a highway built over it, tore down the highway, and daylighted the stream. Now it's a linear park running through the center of the city, and it's become one of the most popular public spaces in Seoul. The temperature along the stream is several degrees cooler than the surrounding streets. People go there to walk, to sit with their feet in the water, to escape the intensity of the city.
That project faced enormous opposition when it was proposed — businesses worried about traffic, people said it was a waste of money. Now it's seen as a transformative success. The lesson being that these interventions often have to fight against a kind of imagination deficit. People can't picture what they're going to get until it exists.
Which brings me to Daniel's second question — the app. Has anyone built a proper discovery tool for urban green spaces? Because I think he's onto something. You can find coffee shops on Yelp, you can find co-working spaces, but finding a quiet bench under a tree or a hidden garden isn't as straightforward.
There have been attempts. There's an app called AllTrails, but that's more for hiking — it's oriented toward trails and nature walks outside the city. Within cities, Google Maps does show parks as green areas, and if you zoom in you can find them, but it's not designed for the kind of mood-based discovery Daniel's describing. You can't open it and say "I want to sit by water" or "I need somewhere quiet within ten minutes of here.
There's also an app called iNaturalist, which is more about documenting wildlife observations, but it can lead you to interesting natural spaces because that's where people are making observations. And some cities have built their own tools — Singapore has an app called Trees SG that maps individual trees and lets you learn about them. But a general-purpose "find me a restorative urban space" app? I don't think anyone's cracked that yet.
The closest thing I've seen is a project called Nature Find, which is run by the Nature Conservancy. It maps parks and natural areas across the United States, but it's not global, and it's more about finding destinations for outings than finding your nearest pocket of calm. There's also Happy City, an organization that does urban wellbeing research, but they don't have a consumer app.
Daniel's idea — an app for wholesome places in the city — actually seems like a gap in the market. You'd need to solve a few problems, though. One is defining what counts as "wholesome" or "restorative." That's subjective. A bench on a busy street might be someone's perfect people-watching spot and someone else's anxiety trigger.
You could crowdsource that, which is what Daniel was hinting at. Let users tag spaces with attributes: quiet, shady, water feature, good for reading, good for picnics, wheelchair accessible, dog-friendly. Over time you'd build up a rich dataset. The challenge is getting enough users to contribute before the app feels empty and people abandon it.
The chicken-and-egg problem of any crowdsourced platform. You'd probably need to seed it with data — maybe scrape OpenStreetMap for park boundaries, use satellite imagery to identify green areas, pull in municipal park data where it's available. Then layer the user contributions on top.
Jerusalem would actually be a fascinating test case for this, because as Daniel noted, there are these well-known parks — Sacher, Gan HaPaamon, the Rose Garden — and then there are dozens of smaller spaces that even long-time residents might not know about. The Jerusalem Botanical Gardens on the Hebrew University campus, for example, is huge and beautiful and surprisingly under-visited. The Tayelet, the promenade that runs from Armon HaNatziv, has one of the best views in the city and plenty of benches, but tourists mostly find it through guidebooks, not through an app.
There's also the Monastery of the Cross valley, which is this surprising pocket of green right in the middle of the city, with olive trees and a sense of being somewhere much more remote. And the railway park, the Park HaMesila, which runs along the old train tracks — that's a linear park that connects several neighborhoods, and it's become a major pedestrian and cycling corridor.
That's another point worth making about Jerusalem specifically. The city has this unusual topography — valleys, ridges, terraces — that creates natural micro-environments. You can be in a wadi, a dry valley, that feels completely separated from the urban environment around it. Those spaces often have olive trees, stone terraces, wild herbs. They're not "parks" in the formal sense, but they're incredibly restorative. An app that mapped those would be valuable.
The app idea is solid. The question is execution. Daniel, if you're listening and you're serious about building this, I think the key insight is that it shouldn't just be a park finder. It should be a mood-based discovery tool. "I have twenty minutes and I need to decompress" is a different query from "I want to spend Saturday afternoon somewhere beautiful with the family." The app should understand the difference.
Ideally it would integrate some of the metrics we've been talking about. Is this space within a fifteen-minute walk? What's the noise level like? Is there seating? Is there tree cover? You could even pull in air quality data or temperature data to help people find cooler spots on hot days.
That's actually a killer feature for a place like Jerusalem in the summer. If your app could tell you "this park is currently three degrees cooler than the surrounding neighborhood because of tree canopy and elevation," that's immediately useful.
I want to circle back to something Daniel said in his prompt, because I think it gets at a deeper tension. He said that to live in a city and get the benefits of being in a city — of which there are many — he needs to find ways to recharge. That implies that the city provides benefits and costs, and the costs accumulate in a way that requires active management. The question is whether we can design cities where the costs are lower in the first place.
Right, that was the premise of the earlier episode he referenced — do cities have to be stressful? And his prompt today is essentially asking: what are the design levers that make them less stressful, independent of whether people can afford to take vacations?
I think the research points to a few concrete things beyond just green space. Noise is a huge one. Traffic noise in particular has been linked to elevated stress hormones, sleep disruption, cardiovascular problems. Cities that invest in noise reduction — quieter road surfaces, sound barriers, electric buses, pedestrianized zones — are directly reducing the stress load on residents.
Air quality is another obvious one. And here the green space and the air quality are connected — trees filter particulates, they absorb pollutants. But the placement matters. A row of trees between a busy road and a residential area can significantly reduce the pollution reaching people's lungs.
There's also the social dimension. Jan Gehl, the Danish architect and urban designer, has spent his career studying what makes public spaces work. His insight is that cities need to be designed for the human scale — for people walking at three miles an hour, not for cars moving at thirty. When you design for cars, you get wide roads, minimal seating, nothing at eye level to engage with. When you design for pedestrians, you get narrower streets, more detail, more reasons to linger.
Lingering is actually the key outcome here. A restorative city is one where people can linger without feeling like they're in the way or that they should be somewhere else. A bench in a plaza, a seat by a fountain, a patch of grass where you can lie down — these are invitations to stop. Bad urban design makes stopping feel uncomfortable or impossible.
Which connects to something I've been thinking about with the Jerusalem light rail developments. The light rail itself isn't necessarily the problem — transit is good, density around transit is good in principle. The problem is when the development around transit stations is exclusively high-rise residential and commercial with no public space budgeted in. You get towers, you get a station, you get maybe a narrow sidewalk, and that's it. There's no third place.
Third place being the sociologist Ray Oldenburg's term — the place that isn't home and isn't work, where you can just exist without spending money. Cafes, libraries, parks, plazas. Cities that lack third places are cities where you're either productive or you're at home, with nothing in between.
But they're infrastructure. They're as essential to urban health as sewage systems and electrical grids, just for a different dimension of wellbeing.
I want to push on something, though. We've been talking about green space and quiet spaces as universally good, and I think they are. But I also think there's a risk of designing cities that are so optimized for calm that they become boring. Daniel mentioned going stir-crazy in the Irish countryside. A city needs friction, serendipity, unpredictability. The goal isn't to eliminate stress entirely — some stress is stimulating, it's what makes a city feel alive. The goal is to give people the option to step away from it when they need to.
That's a really important distinction. The biophilic city isn't a sleepy village. Singapore is biophilic and it's also intensely urban — it's dense, it's fast-paced, it's commercially aggressive. The green spaces are woven through all of that, not replacing it. You step out of a high-rise office building, you walk through a tropical garden to get to the metro, you emerge at a hawker center surrounded by trees. The city hasn't been de-urbanized; it's been made more livable.
The question for a place like Jerusalem becomes: what's the right balance? You've got a city that's ancient, topographically complex, politically fraught, and growing fast. The current development model seems to be: build up, build dense, get the light rail in, and hope the market sorts out the rest. The pushback, which Daniel is voicing, is that this model is producing a city that's stressful and unaffordable, and the very people who give Jerusalem its character are being pushed out.
That's where the green space question intersects with the housing affordability question, which intersects with the economic opportunity question. They're not separate issues. When a city becomes unaffordable, the people who leave are often the ones who create the informal third places — the artists, the small shopkeepers, the people who organize community events. You can't just add parks and expect the city to feel vibrant if the social fabric is fraying.
There's a concept in urban planning called the "just city" approach, associated with Susan Fainstein. The idea is that urban policy should be evaluated against three criteria: equity, democracy, and diversity. Equity means fair distribution of costs and benefits — including green space. Democracy means residents have a real say in decisions. Diversity means the city accommodates different kinds of people and different ways of living. If you evaluate Jerusalem's current trajectory against those three criteria, it's not scoring well.
That's the bleakness Daniel was trying to steer away from, so let me pull us back toward the constructive. What would a restorative Jerusalem look like, if you were designing from scratch?
From scratch is a fantasy, but working with what's there — I'd start by protecting and connecting the existing green corridors. The valleys, the wadis, the terraced hillsides that haven't been built on yet. Make those the spine of a green network. Then I'd mandate that every new development, especially around transit stations, includes publicly accessible green space at ground level — not a token planter, but actual usable space. I'd invest in street trees aggressively, targeting the neighborhoods that currently have the least canopy. And I'd create a dedicated municipal office for public space quality — not just quantity, but quality: seating, shade, water fountains, maintenance.
I'd add: daylight some of the buried streams and valleys that have been paved over. Jerusalem sits on a watershed — there's water moving through the city that's been hidden for decades. Bringing some of that back to the surface would create linear parks that also help with drainage and cooling. And I'd invest in making the existing parks better connected — better paths, better signage, so you can move from one green space to another without always having to navigate busy roads.
The connectivity point is crucial. A lot of Jerusalem's green spaces are islands — you drive to them, you park, you enjoy them, you drive home. They're destinations, not part of the daily fabric. The railway park is a step in the right direction because it's a corridor that connects neighborhoods, but there need to be more of those.
This brings us back to the app question in an interesting way. If you built a green space discovery app for Jerusalem, one of the things it could do is show people how to navigate between green spaces — "here's a walking route that takes you through three parks and a quiet residential street with good tree cover." That's information that exists in the heads of long-time residents but isn't available to newcomers or visitors.
Daniel mentioned crowdsourced maps for coffee shops and co-working spaces. The difference with green spaces is that they're public goods — nobody has a commercial incentive to promote them. A coffee shop wants to be on the map because it drives business. A park doesn't have a marketing budget. So there's a market failure in information about public goods, and an app could help correct that.
Though I will say, some parks do have advocates. The Gazelle Valley has a very active friends' association that runs tours and educational programs. The Jerusalem Botanical Gardens has its own app and membership program. But those are the exceptions. The small neighborhood park with three benches and a swing set — nobody's promoting that.
Alright, let me try to synthesize what we've covered, because Daniel asked for concrete takeaways and I want to make sure we deliver. On the metrics question: the WHO baseline is nine square meters of green space per capita, with access within a fifteen-minute walk. That's the minimum. Better cities go beyond that, and they focus on distribution, quality, and connectivity, not just total acreage. The research supports that access to green space has measurable effects on mental health, cognitive function, and physical wellbeing.
On the design principles: think biophilically, not just in terms of parks but in terms of the whole urban fabric. Street trees, green walls, daylighted streams, quiet courtyards. Design for the human scale and for lingering. Make sure there are third places where people can exist without spending money. And treat noise reduction and air quality as public health interventions, not just amenities.
On the app question: there's no dominant player in the "find me a restorative urban space" category. There are partial solutions — AllTrails, Google Maps, city-specific tools — but nothing that does mood-based discovery of urban green spaces. The opportunity is real, the challenges are the cold-start problem and the subjectivity of what counts as restorative. A crowdsourced approach with good initial seeding could work.
I think the deeper takeaway, which ties both of Daniel's questions together, is that we shouldn't have to choose between the benefits of city life and the restoration that nature provides. The best cities provide both, woven together so that the transition between them is seamless. That's not a luxury — it's increasingly what defines a successful city.
Now: Hilbert's daily fun fact.
Now: Hilbert's daily fun fact.
Hilbert: In 1972, a meteorite fell on the Kuril Islands containing a mineral called ringwoodite, which trapped water inside its crystal structure at concentrations that suggested the Earth's mantle might hold several oceans' worth of water locked in its rocks.
The Earth's mantle is basically a giant water balloon made of rock.
I have follow-up questions that I don't think we have time for.
That's going to sit with me.
Here's the forward-looking thought I want to leave with. The cities that will be most livable in twenty or thirty years aren't necessarily the ones with the most dramatic architecture or the fastest economic growth. They're the ones that get the fundamentals right: housing that people can afford, green space that people can actually use, and public spaces that invite people to stay rather than hurry through. Those things aren't glamorous, but they're what determine whether a city nourishes its residents or drains them.
This has been My Weird Prompts. Thanks to our producer, Hilbert Flumingtop. If you enjoyed this episode, leave us a review wherever you listen — it helps other people find the show. We'll be back soon with more of Daniel's weird prompts.
