99% Invisible - 355- Depave Paradise

Episode Date: May 29, 2019

Mexico City is in a water crisis. Despite rains and floods, it is running out of drinking water. To solve the scarcity issue, the city began piping water in from far away as well as from aquifer below ground, creating yet another problem: the city began to sink as the moisture was sucked up and out from below. Meanwhile, rainwater which should be replenishing the ground can’t penetrate it thanks to impermeable paved surfaces above. Uneven ground and crooked buildings reflect this subterranean crisis on the surface, misshaping the city’s infrastructure and architecture. Depave Paradise

This is 99% invisible. I'm Roman Mars. When you're on a highway stuck in bumper to bumper traffic, all cities start to feel the same. It's easy to forget that you're in a particular place on the Earth's surface, a coast or a bay or a desert or a plane. Mexico City is one of the biggest, busiest, trafficiest cities in the world, but it's also a highland valley, over 7,000 feet in the air, surrounded on all sides by volcanoes. Sometimes these volcanoes spit up a little fire and smoke to remind people of the volatile

geology all around them. But about a millennium and a half ago, a volcano called Sheetlay, fully erupted. Molten lava poured into the valley, destroying an indigenous city and covering 30 square miles in a bed of volcanic stone. Today, most of this lava field has been paved over, with roads and buildings and parking lots devoured by the largest city in North America, Mexico City. That's producer Emmett Fitzgerald. But in the midst of all this urban sprawl, there's one spot where you can still get a good look at that old volcanic rock.

So you can see now in 2019 rocks that are exactly the same as 1,600 years ago. This is Pedro Camarena, he's a landscape architect and we're in the Pedro Gal they sign on hell ecological reserve. It's a small park in South Mexico city that contains the last remnants of the old lava field. Looking down at the ground, you can see swirls and folds in the rock.

How the lava was moving as it cooled all those centuries ago. Yeah, you can see that, that ripple. Yeah, oh yeah, look at that. In Spanish or Cordones. In English, El Pijegal means the rocky place. And it's a fitting name. The ground here is made of purplish black stone and covered in bright green light in. Dry brown grasses are growing up through the cracks, but Pedro says that when the seasonal rains come,

this whole landscape will transform. In rainy season, it turns green and a lot of corals from orange, red, yellow, purple, blue, a lot of wild flowers. So this is beautiful. Pedro, Camarena, is probably the Pedro Gauls number one fan. Here in the Pedral, there are 300 of different species of plants. There are two or three endemic species.

Only here in this place, you can find that one is an orchid, and the other one is a cactus. There's also a tiny little frog that only appears in the rainy season, but by night. But some nights you can stay here in this place and listen to frog the little frog. Very very is magical and many people, even me, are very grace about this landscape. Pedro is not the first architect to fall in love with the betrugal. Back in the 1940s, this love of field became the muse of the great Mexican modernist Luis Baragon. Baragon is a giant of Mexican architecture. He's famous for designing simple cubic houses painted with bold, bright colors, yellows and reds and fuchsias.

His vivid, single-color walls are like the perfect Instagram background. And Baragon designed some of his most interesting houses among the rocks of the Patriot Gal. But in attempting to build harmoniously with this volcanic landscape, he may have accidentally led to its demise and contributed to an ecological crisis that threatens the future of the entire city. Luis Baragon moved to Mexico City from Guadalajara in the late 1930s. The city was in the middle of a building boom and amidst all that construction and growth, the Pedro Gal about 10 miles south of the city center was one of the few places that

remained completely undeveloped. Baragon used to explore the lava field on weekend hikes with his artist friends. Baragon, like a lot of other artistically-minded people, including Diego Rivera, became enamored of this place. This is Keith Egnor. He is an architectural historian at the University of Oregon, who wrote a book about Luis Baragon. He says that Baragon fell in love with the Pedro Gal for its physical beauty, but also because the landscape felt distinctly Mexican. It was a place that the Spanish had never tamed, had never colonized. It was a place with, you know, views of the

volcanoes that were so central to a lot of, you know, Mexican mythology and Mexican history. And Baragon decided to build there. He came up with the plan of building houses, modern houses, and gardens on this again very distinct volcanic site. He called the project Los Hardines de la Péderigal. For years this uneven rocky landscape deterred would be developers, but Beragon saw the lava as an asset. And rather than breaking up the lava and

carting it away and trying to level off the ground as other people might have done, Baragon developed this idea to keep much of the lava and the native vegetation in place. This idea was inspired by architects like Frank Lloyd Wright, who believed that the design of a building should reflect the landscape on which it was built. Just as Wright designed his famous falling waterhouse around the spectacular waterfall in Pennsylvania, Beragon wanted to design homes inspired by this majestic lava field. And so he decided that all houses in the Patrick Hall should be simple and modern and made from basic local materials. Streets should follow the natural contours of the rock,

and lots should be kept really large, as much as 30,000 square feet. And that houses only take up a relatively small percentage of those lots, the rest to be left to gardens. Baragon was obsessed with gardens. This could be apocryphal, but supposedly he used to say, I don't build houses with gardens, I build gardens with houses. And he wanted the gardens of the Pagegal to be oaths to this unique volcanic landscape.

The substantial portion of the original lava should be left on site, and only small patches of lawn might be used, distinct native trees and shrubs were to be left in place and cultivated. Beragon began working in the Pedrogol in the late 1940s. His first houses were carefully nestled among the rocks and integrated seamlessly with the volcanic landscape. The gardens featured little stairways cut into the stone that allowed you to move through the space. There's even a spot in one of the houses where a huge piece of lava comes through the wall. And if all this sounds pretty expensive, well, it was. Barragans' goal was to convince wealthy professionals to escape the crowded noisy city center in favor of the fresh air and beautiful scenery of the lava field. And he hired a photographer named Armando Salas Portugal to really capture the vibe.

Salas Portugal's beautiful photos of well-to-do Mexican families wandering through the rock gardens helped sell Paragon's lava lifestyle to the Mexico City Elite. You can live in the paradise, very exotic place with a lot of lava. Here's Pedro Camarena again. Nobody's around you. You came with your Cadillac 57 or your Buick 59. And you look like a curry grant or something like that. So many people make succeed.

Yes, we want to live like that way, no? I mean, it sounds pretty cool to me. Right? You live in this rugged wilderness, just a short drive from your downtown office job like a sophisticated cowboy. Yeah, but new cow is with a carry like instead of a horse. If I have money at that time,

I for sure bought a house in the Pentagon, of course. If you aren't able to visit Metzgosody, Armando Salas Portugas' photographs are probably the best way to experience Barragán's architecture and his vision of harmony between building and landscape. But the truth is, that vision never really came to pass in the real world. In the early 1950s, Barragán got bought out of the project. And soon all his utopian ideas about how the landscape should be developed went out the window. The city was growing at a breakneck pace, and here was this source of cheap land. And so you can see in these aerial

photographs, El Pedragal in 1950, there's a few houses and roads there by 1959, the place is densely packed with houses and very much built up. The houses got bigger and the gardens got smaller. And newcomers to the area didn't seem to share Baragon's reverence for the lava. They covered up the rocks with dry waves and lawns and gardens full of non-native plants. And it's easy to think about this story as a kind of eco-architectural paradise lost.

In part, because of the way people talk about Louis Baragon. He's kind of come down to us in the architectural hegeography and the literature as this mystic monk sort of remote from modern life in many ways. And there's certainly truth in that. But at the same time, he was also a very successful businessman, even a rather repacious real estate developer. Ignor says that Baragon knew what he was doing. That paradise was always very ephemeral.

It was never really meant to last. And again, I don't think Baragon really expected it to last, and again I don't think Baragon really expected it to last. Between the 50s and the 80s, nearly the entire lava field was developed. Today about a half million people live on top of the petrogon. There are fancy neighborhoods and poor ones, but aside from the little preserve where our story began, the lava rock is basically gone. And it would be fair to put that all on the West Beragon. But the irony is, as much as he genuinely loved that lava landscape,

in a way he facilitated its demise. That project of beautiful houses in Jarines del Pedregal, they trigger the urbanization in South Mexico City. And then, it starts to develop urban development, and that's the fat of error. Pedro Camarena thinks that developing El Pedro Ga was a fatal error, not just because the rocks look pretty, or were home to some cool plants and animals. He says that covering up this unique geology contributed to a deeper problem, an ecological crisis that's playing out in Mexico City today. A crisis rooted in the city's extremely complicated relationship with water.

Yeah, for Mexico City, the trouble with water is quite complex and it all starts in the moment that someone decided to build a city upon a lake. This is Loreta Castro Rivera. I'm Loreta Castro Rivera, I'm an architect and an urban designer and I do design, design for the city and design with water. Castro Vergara says that the Valley of Mexico is actually more of a basin. It's a closed basin. It's like a bowl, which has no natural water exits.

So when it rains, all the runoff concentrates in the lower areas of the basin, and this bowl starts filling up. For centuries, the basin was filled with a series of rainwater lakes. The Aztecs built their capital, Tenochtitlan, on an island in the middle of one of those lakes. They built causeways and canals and floating gardens. It was like the Venice of Mesoamerica. But when Spanish conquistadors sac Tenochtitlan, they rebuilt the city as if it was just

any old city in Spain, with a centralized grid. So that's when real trouble starts happening. Nearly every year when the seasonal rains came, the colonial city would flood. And we're talking serious flooding. After the flood of 1629, Mexico City was under water for four years. And in that moment, the government, the vice-roy decided to open the first canal that would start draining the lake system. Over the course of the next several centuries, Mexico City built an elaborate system of tunnels designed to evacuate rainwater out of the basin and prevent flooding. Little by little, the city drained the lakes

and expanded out over the dry lake bed. But Mexico City also suffers from a second water problem, one that seems almost paradoxical. Even as it gets inundated every year with rains and floods, the city is running out of water. In the middle of the 20th century, Mexico City's population exploded, and all of those people needed to drink.

The seasonal rain could have provided a reliable source of fresh water, but Mexico City had just built a massive system of infrastructure designed specifically to get rid of it. And now, with the 23 million inhabitants in the city, there is not enough drinking water to satisfy the necessities of all this enormous population. Today, many neighborhoods in Mexico City don't have reliable running water.

And then, when the rainy season comes, those same neighborhoods get far too much water, all at once. So we live in these paradoxes of urban floods and water scarcity. To solve this scarcity issue, the city took two approaches. They piped water in from far away, and they pumped it up from the aquifer blow ground. Which in turn created a third problem. In the early 20s of last century, some engineers saw that the city was sinking. This is Manuel Peralo Cohen, he's director of the Institute for Social Research

at the National Autonomous University of Mexico. Some buildings sank five centimeters per year, and some of them thin. The reason was pretty straightforward. As more and more people took more and more water out of the aquifer every year, the muddy lakebed soil began to crack and crumble like a stale cookie. And that's why the city began to sink.

Today, Mexico City is pumping water out of the aquifer twice as fast as it can replenish, and the city has sunk about 30 feet over the past century. If you walk around Mexico City today, you can see this in the landscape. Crooked skylines, sinkholes and places where the ground is completely uneven. Mexico City is flooded, thirsty, and sinking. And climate change is only going to make all of it more extreme. It's an impossibly complicated problem with no easy solution. But with impossibly complicated problem with no easy solution.

But with impossibly complicated problems, you have to start somewhere. And Pedro Camarena thinks that one place worth considering is the lava fields of El Pedro Gal. So let's take a look at what is the Pedro Gal I'm going to show you. Yeah, yeah. I'm going to show you why these water run very, very easy in this lava field. Pedro is one of several architects who have started thinking about ways the city could recharge its groundwater aquifer. In most places, recharge just isn't possible. The ground beneath the old lake is made of clay that retains water on the surface and prevents it from flowing underground.

But in a few places around the edges of the old lake, the landscape is rocky and permeable. And you think it'll pay the regal is probably the best place. The best place, of course, because because lava fields are the most permeable geology on earth. Back in the Pagogal ecological reserve, Kamarena bends down and points to a piece of lava rock. Look, there's a lot of holes, there's a lot of pores. Very porous stone, thank you. It looks like one of those pumice stones that people use in the shower to scrape dead skin off their feet. Yeah, more or less.

Pagro says that for years when rain fell on the Pedro Gal, the water would easily trickle down through this porous stone into the aquifer below ground. Can you think you've came a big, big storm? Do you think you can find a lagoon here? Of course not. But the same cannot be said for most places on the old lava field. Because apart from this ecological

reserve, nearly all of the porous volcanic rock is gone, covered up by layers of impermeable concrete. And so, when the rains come, the water just runs off the pavement into the sewer system. But Pedro Comorano wants to change that. The only thing we have to do is to depave the rocky fields in the south. We have 80 square kilometers of big lava field. Obviously it's very, very urbanized now, but we can depave. Do you understand what I mean?

What he means is get rid of all the unnecessary pavement that's plugging up all those volcanic pores Camarena wants to depave parking lots and medians and create volcanic infiltration zones where rain water could flow back to the aquifer You have to be cautious. You can't create an infiltration zone next to a toxic waste dump or you could contaminate the whole water supply But Pedro wants to carefully peel back the city's concrete skin. To expose the lava and try to restore the lava field. Because the old lava field is still there beneath all the asphalt. If you go to Los Hardines del Péthedigal today, upscale neighborhood that Luis Barragón started back in the 40s, you can catch a glimpse of this buried landscape, little pieces

of lava poking through the grass and the concrete. For the most part, though, it looks like other affluent neighborhoods in Mexico City. A lot of lawns with sprinklers. So they prefer to put a lot of grass and let me tell you, they spend, now days, they spend a lot of money in irrigation. But Pedro wants to shift how people in Mexico City think about gardening. A while back, he was asked to design a garden to go with a public art sculpture that was built in the Patriot Golf 40 years earlier. And instead of planting a bunch of flowers and shrubs, he just started digging. So I create that garden only by excavating digging.

Gardening by subtraction. Pedro calls this landscape archeology. We start with three guys, old guys, digging like archeological site. They start to remove plants then soil and then then starts to appear the lava field beautiful. It's a lot more work than planning tulips but Pedro says that people in the Pagregol can do landscape archaeology on their own property, uncover the lava and build baragon style dry rock gardens

that don't require any irrigation. But it's a tough sell. People want gardens that look like Versailles. Yes, we are very dependent, emotionally dependent, in Europe. We still design gardens like in France. I mean, it's ridiculous. Because we don't have the landscape of France, we don't have the weather, we don't have the soil,

this means very different. But Pedro told me that there is one house in Los Hardinis del Péritigal, where you can still see a true Mexican lava rock garden. It's actually one of the first houses built in the area, designed by Baragon himself, back in the 40s. The property underwent a lot of changes in the decades since. But a few years ago, a new owner, a man named Cesars Avantes, decided to restore the house

to the way he had looked in Baragon's day, and Pedro convinced him to uncover the original lava rock. And he did it. And now everybody told me, Pedro, you have to see, you have to go to Cesar House to see what's happened there. Have you seen it? No, I asked him and he said, come, whatever, whenever you want, but I don't have time. I, on the other hand, have plenty of time.

I am Cesar Cervantes and we are at Casa Pedra. Cesar grew up in this neighborhood, and says that back then no one really wanted to see visible lava in their garden. And I remember even my father covering or getting rid of visible lava, favoring grass or assuming bulls too late. When Cesar bought this house, the previous owners had covered up the original baragon rock garden with an astroturf pudding green.

But Cesar and his team started doing a little landscape archaeology. We start removing and removing layers, layers of grass, baked grass, and cement. And slowly the original lava field began to re-emerge. As he was coming back to its original condition, he was really, really, breathtaking. And it really is. Cesar kindly let me take a tour of his home with a guide named Mariana Esqueda. Before we got to the garden, Mariana showed me the house. The walls are thick and heavy and painted this delightful shade of pink. As she opened the door, I was yammering on about something or other, and the house kind of took my breath away.

The garden of Pichagall, like what was he trying? Wow. It just, it sounds so quiet. Yes, I know. It's one characteristic on Baragon. Not you can feel the silence, the tranquility. Yeah, it feels almost like a church. Yes. After showing me around the house, Mariana led me back to the garden.

We scrambled down a rocky path, and then suddenly we're surrounded on all sides by porous black lava. It was unlike any garden I've ever been in. More like a nature preserve filled with Mexican plants and animals. Like succulents, like cactools. I mean, look, there's a... Yeah.

There's like lizards right there. There's half manilissars everywhere. Ha, ha. It feels... Yeah, it feels... wild. It's really beautiful. Sayzar says that when his neighbors first saw the rock, it was clear that they didn't even know they'd lived on top of a lava field. Where did you bring this lava from or how did it appear here?

But Pedro Camarena hopes that if more people see these rocks, maybe they'll follow suit and dig up the lava in their own backyards. Rock gardens in rich neighborhoods are not going to solve the water crisis, not even close. But every bit of lava that gets uncovered is a tiny step in the right direction towards rebalancing the city's relationship with its groundwater. A huge thank you this week to the fantastic environmental reporter Zoe Schleiner, her great piece in courts about Mexico City's water problems clued us into Pedro Camarena and his work. Zoe has written a lot of great stories about water and climate change and other environmental issues.

You can find links to more for work on our website at 99pi.org. After the break, we'll talk about the bigger picture and what architects and designers are trying to do to solve Mexico City's water crisis. So I'm back with Emmett in the studio and we want to take a second to zoom out and talk a little bit about the bigger picture when it comes to the Mexico City water crisis. Yeah, and if you talk to Loreta Castro-Vigara, who is one of the architects that we heard from in the story, she'll tell you that it's a question of design. Design is really a key element in this situation.

For us, it's the language we speak with water. Oh, I like speaking in the language of design. Yeah, I know. She sounds like a 99 PI disciple. Dream guest. You know, Loretta says that there's really no, there's no silver bullet design solution for Mexico City's problems.

But what she kept coming back to with me was that fundamentally the city has to change its relationship to rain. So what do you mean by that? Well, you know, Mexico City is different than a lot of other cities that are facing water shortages around the world and that they do get rain. It rains, it rains, that you know, Cape Town,

South Africa would love to have as much rain as Mexico City does. But because of this history with flooding, which we heard about in the piece, you know, they've learned that rain water is bad. The problem for us is that we see water as our enemy. We have learned that water that floods is a problem. And we've learned that for the last 700 years. So it's really hard to change the way in which we see rainwater. But they really have to because that rainwater is an asset that has been wasted for so long.

We spent literally hundreds of years focusing on get the rainwater out of the valley as fast as you can so that we don't flood out. And, you know, the consequence of doing that for so long has been like the desiccation of the watershed. So this is Enrique Lomnitz. And Enrique is the co-founder of an organization called Isla Urbana. It means like urban island in Spanish. And the whole goal of Isla Urbana is to try and take advantage of all that rain, to try to flip the equation on its head and say, let's turn this rain water into an asset. And to do this, what they do is they design and install rain water harvesting systems on people's homes. And Enrique says that this makes sense for a couple of different reasons. One, because it provides people with reliably clean water. And two, because it reduces the pressure on the groundwater aquifer.

So, rainwater harvesting systems, like we use, they help you avoid pulling water out of the ground, and they help you avoid kind of putting water into the sewage system, and they help a family in parts of the city that are having big water problems. And Rique helped launch the organization in 2009 in a neighborhood that had particularly bad water problems. And RIKI helped launch the organization in 2009 in a neighborhood that had particularly bad water problems. Like people are starting to open their taps and have like brown water come out of the tap, no, or just not have any water coming out of the tap sometimes for weeks on end. So are there's birds on here and on the tape there?

Did you record that? Yeah, yeah, I saw it doing RIKI from some rural town that apparently is filled with parakeets. There's a lot of birds on the Skype tape. All right. Okay, there we go. But anyway, his organization is a lot of urban. They designed these systems for individual homes.

And this system basically collects rainwater from the roof of the house, filters out all the kinds of impurities that you might have, and then stores it in a big tank for daily use. So in some ways it's a pretty simple sort of design intervention, but the thing that that makes it the work really challenging is that you can't just mass produce this system and ship it out. Every house is different. So every rainwater boosting system is like a custom install and every family has to be trained and taught how to use a rainwater harvesting system and what it's for and how to use it and how not to use it and what to be careful of. And so the work ends up being really social. You can't just drop the technology on people.

You have to cultivate relationships and get them on board. And so can you drink the water? Is it clean water? No, it's not clean enough to drink, but it is clean enough for just about every other household you use who could have. That makes up the vast majority of the water that a home uses. What is the scale that they're working on? How many of these water systems are they trying to get installed around the city?

Yeah, so at this point, they've built about 11,000 rainwater harvesting systems. So, you know, it's a lot, but it's not a lot in the grand scheme of things. And mostly they've been doing this on a fairly small scale and going kind of neighborhood to neighborhood, very grassroots approach. But things even in the last couple of years are really starting to scale up. And Mexico City just elected a new mayor. Her name is Claudia Scheinbaum, and she's a scientist who spent her whole, a scientist being elected mayor of cities. It's not a normal background for a political candidate

in any country really, but she spent her whole career studying environmental issues, water issues specifically. She's got an engineering background, so this is all really up her alley. And since her election, just know, just this past year, the government, the city government has started to work much more closely with this Lyrebana and they really want to push rainwater harvesting on a really large scale.

The Mexico City government was like, dude, this is an important project and we need to do it huge. Knowing all of the parts of the city that don't have water. And we're installing, we're gonna be installing 10,000 rainwater harvesting systems there this year, and if all goes well, finance the installation of like 100,000 or more rainwater harvesting systems over the next two years. So it's definitely a large scale experiment at this point,

and it's kind of one of it kind in the world. Well, so they're like scaling up like 10 times, like for about 10,000 to 100,000, that's amazing. Yeah, it's really cool to see, but even Enrique isn't trying to argue that rainwater harvest thing is the solution. It's really gonna take a whole basket of different strategies to get Mexico City out of this mess.

We're gonna get out of this situation by doing a whole bunch of things together, but that fundamentally just create balance between how much water we actually put just create balance between how much water we actually put into the ground and how much water we pull out of the ground. It's fundamental is that in its most basic essence. With that in mind, Loretta Castro-Vegada, the architect we heard from earlier, is focusing on designing parks and other public spaces that also function as water and infrastructure. So, you know, like a public sister

and they can collect rain for a lot of different people or a public park that has a ground water infiltration component where you've actually got rain water flowing back to the aquifer. And so her goal is to create a whole network of green infrastructure so that when those rains come, the city can take that water in and make use of it. In a sense in which the city could really become a sponge. So when we have one of these rainstorms,

all these public spaces somehow are able to hold rain water and keep it there until the storm passes. You know, in that way, theoretically, a big rainstorm could be something that people are looking forward to and hoping for rather than something that they fear. Because it would both collect water that they need and also mitigate flooding because the water would be drained to the aquifer instead of being on the surface and trap their destroying things.

It's true. It's true. Yeah, if you can hold that water, you're also preventing that water from turning into dangerous runoff that causes problems. And, you know, I mean, you shouldn't go too far with that. Like, flooding requires its own, you know, in order to solve the flooding problem, there's other things that are needed. There are architects that are actually thinking about, you know, bringing back remnants of

the old lake systems as ways to allow water to flood into these spaces that can hold and retain water and keep people safe. There's all kinds of things that architects and designers are thinking about. And engineers, too, the big problem is leaks. The whole water system is old and filled with leaks. Some people estimate they're losing as much as 40% of water in leaks. So, in terms of low hanging fruit, that's a great place to start. Also wastewater reuse.

You know, there's so many different things that need to happen. And the red is point is basically like, we need all of it. There's not one. We're not waiting around for the best solution. We need, it's in all of the above strategy. Because what I see at this moment is that we have the enough infrastructure to keep the city safe for 30 years. So we can think on to a window of 30 years in which we have a very big opportunity of putting up

all these alternate water management strategies, right? Then we could really use this 30 years for our best benefit. And in 2050, not have this problem of we have no more water and the city disappears now because we also know from history that many cities disappeared because of lack of water right? Wow I mean it's kind of terrifying thought like a real existential crisis about the existence of an entire city because of water. Yeah and an absolutely massive city you know 22-23 million people it's really scary. But, you know, I mean, honestly, everyone that I talked to seemed a little more optimistic than I was expecting.

And I think that that optimism comes from the sense that the city really feels like it's undergoing a real shift right now in how it thinks about water and how it deals with water towards, you know, really embracing all the rain that flows into the basin. And the question is just like, can that shift happen fast enough? We can make another interview in 15 years and we'll see if it's working or not, right? Yeah, let's book her right now. Yeah, all right. Thanks so much. Thank you.

99% invisible was produced this week by Emmett Fitzgerald, mixed in tech production by Shereef Yusuf, music by Sean Riel. Katie Mingle is our senior producer Kurt Colstad is the digital director. The rest of the team includes senior editor Delaney Hall, Avery Trufflement, Terran Mazza, Vivian Lee, Sophia Klatsker, Joe Rosenberg, and me Roman Mars. This episode was supported by the Alfred P. Sloan Foundation,

enhancing public understanding and engagement with science and technology. More information on Sloan at Sloan.org. We are a project of 91.7 KALW in San Francisco and produced on Radio Roe in beautiful downtown Oakland, California. 99% invisible is a member of Radio Topia from PRX, a fiercely independent collective of the most innovative shows in all of podcasting. Find them all at radiotopia.fm You can find the show and join discussions about the show on Facebook.

You can tweet at me, at Roman Mars and the show at 99PI Ork. We're on Instagram, Tumblr, and Reddit too. But the beautiful lava field that we call home is 99pi.org. Radio Tapio from PRX.