What exactly is mud? Where does it occur and how does it factor into animal behaviors and human activities? In this multi-episode Stuff to Blow Your Mind exploration, Rob and Joe immerse themselves in the mysteries of mud.
Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Hey you welcome to Stuff to Blow Your Mind. My name is Robert Lamb.
And I'm Joe McCormick, and we're back with part three in our series on mud. Yes, mud, regular mud, wet soil, especially of the clay and silt sized particle variety. So in previous parts of the series we talked about what mud is, what its physical properties are, the role it played in the history of shaping Earth's continents, and how life colonized those continents. We talked in the previous episode about many animal behaviors that relate to mud. We talked about pigs wallowing in mud, Arnold Schwarzenegger wallowing and mud. We talked about mud skippers and other animals whose lives involve mud in one way or another. But of course, mud also plays a big role in human culture and human technology, even in the building of many important human settlements. So that's what we're going to focus on today. Mud, especially as a building material for humans.
Yeah, yeah, the mud brick, especially because you know, we could build things out of mud, I guess without forming some sort of a a brick or or or you know, something to to stack, something to use, but it would be messy, it wouldn't be very effective. And that's where the mud brick comes into play here, and the ability to turn mud into this thing that then then can be mass produced and used to build a variety of things. Brian M. Fagan features several chapters that touch on mud bricks in the seventy Great Inventions of the Ancient World. In a chapter on dwellings with Kate Spence, it's pointed out that we we absolutely can't consider human dwellings and the development and advancement of materials and techniques with also taking into account the shape of human culture at a given time and the environment in which they're constructed.
The series of episodes has repeatedly just forced me to think about the interesting web of back and forth interactions between inorganic geological conditions in certain places on Earth and the life and culture that arises there.
That's right, that's right now. On that first count, that idea of you know what, you know, where are people going? Where are they living their lives? In ancient times? You know, as we've discussed before, there are modes of life and technology that makes sense if you're settled long term in a single area. But other modes make more sense if your nomadic or semi nomadic, as many of our global ancestors were. So for nomadic peoples, it might make more sense to depend for shelter on some manner of say wood frame plus high tense scenario, or to depend on very fixed, even naturally occurring shelters that you could take advantage of periodically, such as caves. There's also room in this for more permanent structures that seasonal settlements, places that you're going to come back to again and again, you know, when the seasons allow it, or the you know, crops, movement of animals, whatever happens to be the case, and then there are going to be you know, other modes of temporary constructions that are going to make sense as well. But the other main point is that of climate and environment. What is possible in a given area from a local material standpoint, would for example, makes an excellent material for building in ancient times as well as in our own modern world, But if it's harder to come by, if it has to be imported, et cetera, then it may make more sense to use it only for key roles, such as for instance, framing and lean more heavily on other materials that are easier to acquire.
Makes sense. Yeah.
Now, Spence does note in their chapter that the thing about many ancient building supplies is that they simply don't survive the passage of time. But we know our ancestors used wood and even bones as tent structures between twenty five and twelve thousand years ago in Eurasia at Jericho, which this book site says at least at the time, the earliest evidence of occupation there dated back to before nine thousand BCE, and it seems that the earliest houses there were built out of quote unquote clay lumps and probably also made use of wooden building frames before they transition to mud brick buildings. For first first circular in nature, and then later they used rectangular designs with multiple rooms.
So tell me about mud bricks.
Okay, So mud bricks are pretty fascinating. I didn't expect to get so into mud bricks, but this book and then another one I'm going to refer to in a bit really get into it and made me appreciate them. So mud bricks are especially useful in arid environments because mud bricks like other forms of solid masonry, are poor conductors. Heat Thick walls of mud brick will slow the rate at which the exterior solar heat is absorbed into the interior environment.
So they're good insulators if you're living in say, a hot desert.
Yeah. And additionally, structures like this, which are still common throughout North Africa, the author notes here, often feature high ceilings and small openings set high in the wall to encourage airflow. Also flat roofs since there tends to be less rainfall to contend with. So it's a design that has stood the test of time. It's a building material that has stood the test of time. Now, the thing is, of course, all buildings in general require upkeep, no matter what you're building in them. Out of modern buildings upkeep as well. But of course mud brick buildings require regular upkeep against erosion. That is specific to the nature of mud bricks, and we'll get into that more in just a bit as well. Now, in the seventy Great Inventions of the Ancient World, later noted in a chapter with Jeffrey P. Killen that mud bricks were also used in the construction of furniture, such as among the poorer classes. In ancient Egypt, wood and ivory were materials of the wealthy, while mud brick platforms served as beds by night and benches by day for common folk.
As a side note on the subject of ancient Egyptian beds, if you've never seen ancient Egyptian the headrests, you should look that up. Where instead of pillows, they would have sort of a stand for your head to lie on, like a rigid stand. I find that really interesting.
Yeah, didn't we discuss this in the Invention of the Bad episode. Yeah, if memory serves, we talked about the work of a researcher who was like recreating these and testing them out.
Unfortunately, I don't remember what the conclusions of that were, but yeah, very interesting. So imagine instead of a soft pillow, you use like a little hard podium for your head to lie on.
Now elsewhere in this book at it also points out that extensive town walls appeared in the sixth and fifth centuries BCE, often constructed of mud bricks, but with stone facing and or rubble filling. An example of this would be the long walls of classical Athens. These were destroyed by the Roman general Sula during the first century BCE, and they had been rebuilt even before that, So you know, it's the nature of fortifications. And then also you know, some of the part of it also is the nature of mud bricks, which we'll come back to. By the third century BCE, mud bricks were a common material in the construction of walled cities among various Mediterranean civilizations, according to Fagan. Now, one something that also comes up in these chapters is that mud bricks would have also been used in the construction of what was considered an antiquity, one of the Seven Wonders of the ancient world, the hanging Gardens of Babylon or the guard in terraces of Babylon that are often attributed to the ruler Nebekinezer, who lived six oh five through five sixty two BCE.
Now, when I was a kid, I had a little booklet that I read a lot that was about the seven wonders of the ancient world, and one of them was the hanging gardens of Babylon. And I never understood what the deal with the word hanging was. I was imagining them like dangling from chains, but what were those dangling from? I didn't get the hanging part.
Yeah, and it seems that a more accurate description would be terrast. We're essentially talking about great terraced gardens. So I wanted to get into this a little bit more because you know, obviously, if something's being held up as one of the wonders of the ages during this time and it was made out of mud bricks, mud bricks being something that you know, you might without knowing much about it, you might just think, well, this is a simplistic this is an old fashioned form of construction. Well, well, let's look a little deeper. So I picked up a book. This is a new book came out just this year that we've actually been in discussions with having the author on the show. Even it's such a neat looking volume. It's titled The Seven Wonders of the Ancient World, Science, Engineering, and Technology by Michael Dennis Higgins. It's a great book. It looks at not only what's historically known and or alleged regarding these wonders and how it ties into what we know about the geology of the regions where these wonders were located or thought to be located, but also what recreation in the modern world might look like so, Chapter three of the book deals with the Gardens of Mesopotamia because while the traditional view Higgins rides is that the gardens were set in the walled city of Babylon and what is now central Iraq just south of Baghdad during the sixth century BCE, there is also growing support for the idea that they weren't located here at all, but were in nineva during the seventh century BCE, in what is now northern Iraq near Mosul Oh.
So that would make sense because then I would assume that would mean they wouldn't be the gardens of Babylon but of Assyria, right, because Ninevah was the capital of Assyria, but still would have been between the rivers, still would have been Mesopotamia.
Yeah. One thing that that Higgins stresses, and we have to keep in mind with the Wonders of the Ancient World, the Seven Wonders of the Ancient World, is that these were the these this was like a list that was that was put together in the Hellenistic world and the concerning things that were often far away, and this is especially the case. These were the this, these were the east. This was the eastern most wonder on the list by a considerable margin, and they it was so far away that you could basically say whatever you wanted and it would not be questioned.
I've often thought of the writings about these as kind of the the Forbes travel Guide of the ancient Greeks, but maybe with some shaky sword.
Yeah, because again, the idea of the Seven Wonders of the Ancient World are basically a first century BCE creation, and in this particular case, they're dealing with something from the sixth or seventh century BCE. Higgins writes, quote, we will never know definitively the where and when of the gardens, and it is likely that more than one Mesopotamian ruler had remarkable gardens that may have been conflated in stories and accounts relayed to the far off Mediterranean world. Higgins also adds this other great little addition. He says, quote, we should perhaps be wary of imposing a modern view of garden life. In one panel from the north palace of Ashurbanipal, king of the Neo Assyrian Empire from six sixty nine through six point thirty one BCE, the king is taking refreshments while listening to music with his wife Amid luxuriant trees, from one of which hangs the severed head of an enemy. So I don't know quite what to make of that, but fair enough.
Well, you like to celebrate your accomplishments, and that can take many forms.
Yes, anyway, onto the bricks. So the role their role in the construction of the gardens would would vary depending on where exactly this garden would have would have been. Higgins writes that there are five ancient descriptions of the gardens. The most detailed stems from Greek writer Deodora Sicolis during the first century BCE, but he does not identify the actual city where this is supposed to be, and he also doesn't name the ruler. All he says is that it is a quote Syrian king. Still, there are a lot of details mentioned in this account, and it specifically mentions bricks. He describes ascending tiered terraces full of abundant platte life, made level with the opposing battlements of the city, opposing as in like there inside the city looking at the their opposite an interior wall. So this particular account describes that the roofs over a series of galleries were layered with stone beams. Then they put down a layer of reeds and bitumen. Then two courses of baked bricks bonded by cement were put over this. And we'll have more on baked bricks in a minute. Then there's a layer of lead to prevent moisture from creeping down, and then enough dirt and soil on top of all that to accommodate the roots of quote the largest trees. So a considerable garden project any way you look at it, like definitely more involved than anything any of us are doing in our backyards. Okay, so I mentioned baked bricks. I want to come back to mud bricks specifically. So Higgins stresses that these were mud bricks were the most important building material in Mesopotamian cities, and this was especially true of Babylon, which had no outcroppings of stone in the immediate area Nineva. On the other hand, up there, there was a local supply of limestone, so they were able to lean on that much more for their construction needs. However, mud bricks were still used there because they were traditional and or inexpensive.
All right, So you could quarry out stone bricks up in Nineve if you need them, But mud bricks are still just cheaper and more efficient in many ways, and you know, there were something people were used to using and they get the job done.
Right right now. The process of making the mud bricks is also very important here, and I thought very interesting. I just never had looked into this before, but in this particular, their mud bricks you used throughout arid parts of the world where people have settled, but these specifically, these would have been sediments washed down the Tigris and Euphrates from what is now Turkey. Then the people would collect the mud and then they would mix in fresh straw. This would give the mud bricks, once they had time to dry, additional strength. And this reminded me of our episode on Pie Create Joe about creating building materials out of ice and how something had to be added, something had to be mixed in there with it to give them additional stability.
What was it? Was it like, I want to say, like chopped up newspaper or straw or sawdust or something to that effect. Yeah, yeah, so fresh straw would be serving the purpose here, and it does seem like it did need to be fresh, and we'll come back to that in a second. Then, so you have the mud you've added in the fresh straw. Then you mold these into more or less uniform brick shapes, and then you leave them to air dry. And then once dry, you know today you have bricks for building all sorts of structures. So this began as mud, but it ends up being sturdy enough to build.
With, right, So there are some pros and cons here. So the pros the big pro of course, is that these are inexpensive and they don't require high temperature, fuel consuming ovens to bake them as you have with with baked bricks. You can make a ton of them. You can use them to build battlements, buildings, et cetera in pretty short order.
So again they're they're cheap, they're fast building material to make them as abundant, and they get the job done right.
And I don't want to imply that, you know, there's just a crude mode of construction, Like obviously there's an art and a craftsmanship to making them, and I think that's key here too, Like the local people knew how to make them. There was a tradition of making them, and that also allowed them to bust them out in massive quantities in a short amount of time.
Oh yeah, I want to be clear by saying like that they're inexpensive, I mean that they're you know, they're inexpensive relative to like quarrying or having to fire the bricks in an oven. But that doesn't mean that they're like junk. I mean this is this is building material that serves its purpose and it is efficient, it's smart.
Now there are cons here. Of course, these are arid environments, but it doesn't mean that it doesn't rain, doesn't mean that there aren't floods, periodic flooding and so forth. So yeah, they're easily washed away or damage during storms. Plus this was impressive, as Higgins points out, the bricks at the base of walls of structures draw up and absorb water by capillary action. The water evaporates, but quote, salts are concentrated and finally crystallize between the mineral grains, causing the mud to flake, weakening the base of the walls. And he also has this was especially true would have been true in Babylon due to the rather brackish ground water.
Yeah. Okay, so higher salt content in that water, more more crystals getting into the bricks.
Yeah, so mud brick buildings while essential for the time period, also required a lot of upkeep, and they would eventually fail. Mud brick buildings would eventually crumble and fall apart, and any resulting bricks would not be reused, nor would the mud. Like you couldn't just like you know, essentially wet it all down and form new mud bricks out of that mud, out of that soil. And it's thought that a lot of this had to do with the fact that at this point it's all it's old straw mixed in there, and it's not going to hold things together as well as fresh straw. So you would get fresh mud from the river, you would add fresh straw to that, and you would just build new new bricks the old side, the crumbled bricks, et cetera. You would just flatten that down as much as possible, and that would service the foundation for the new structure. And it's interesting that resulting mound of old mud bricks is what we call a tell. This is like a rising heap where these would these buildings would crumble, they'd have to be flattened. You'd build a new one that eventually would crumble and be flattened. Higgins rights that over the millennia. Such tells actually lifted the base levels of cities up above the plane, making them more defendable, making the more desirable as places to live and to work and to defend yourself. And therefore the pattern would just continue.
Yeah. And so you can see in the locations or ruins of some ancient settlements, especially in the ancient Near East, that maybe even no buildings remained, but there's just a big mound built up off the ground.
Yeah. So that's incredible. So anyway, the problems of mud bricks were known, even though they were traditional, even though they were inexpensive. Higgins points out that not only is Babylon home to some of the earliest known recorded legal systems, but also some of those laws that were recorded concerned building collapses. It was written that if a building's collapse caused the death of the homeowner, then the builder would be put to death.
Oh wow, that is a strict building code.
Yeah, but you know, it makes sense you're building, I mean, not to say the eye for and eye nature of it, you know, makes it makes sense so much. But just the idea that like, buildings are important and there has to be some sort of you know, some sort of law in place to make sure things are built to code.
Yeah, maybe not death penalty, but builders should be kept to a high standard.
Yeah yeah. And so you know, again, it was known that there could be problems with mud bricks, and it was discovered early on that you could transform mud bricks of a sort into something harder and less susceptible to erosion. Higgins writes, quote, heat changes water bearing clay minerals with their slippery playing card structure, into larger, interlocking crystals of minerals containing less water, which makes a stronger material than is water resistant. He ultimately compares this transformation to kind of a sped up and you know, less sophisticated process of metamorphism that in like in the ground and over geologic time, produces things like marble. And so he writes that many of the great Babylonian structures of the day would have been made of baked bricks, and these would ultimately last so long that they would be reused long after the final fall of Babylon to build such cities as Baghdad. And we see this in other parts of the world as well, Like the bricks stand the test of time, and then the bricks are scavenged in order to build the new cities of an emerging new world.
But these would have been fire bricks.
Bricks, Yes, these have been the fired Yeah, you're not doing this with mud bricks at all, But baked bricks are just that much more durable and and you know, and it's it's inter I was been talking about this with my wife and she pointed out that, you know, a lot of the bricks we see on houses today, like they're pure they're purely ornamental. They're real baked bricks, but they're not like doing much or anything in the way of structural support for the house. Your house isn't built out of bricks. It's built out of wood framing and all the other stuff. But the bricks are there just for ornamental purposes, well, depending on the house. But yeah, in a lot of modern uses. Yeah. Now, Higgins points out that limestone was also used in special instances, but this would have been expensive to import in Babylon, Unlike with Nineveh. The walls of Babylon, however, were also sometimes listed as an ancient wonder in and of themselves. They were made of mud bricks, and the gates faced with baked bricks that were glazed with a glass like blue glaze that was then detailed with yellow flora and fauna things like lions and all. So these walls would have begun depended mostly on baked bricks for their their bulk and their protective qualities. But then you also had glazed baked bricks that made them, you know, beautiful to behold and spoke of the glory of the city and its ruler. So Higgins goes into a lot more detail in the book about all of this, and especially gets into the geology of the region. But I think just what we've we've drawn out here already, it provides a nice glance at the importance of mud bricks in the ancient world they're pros and cons, and also how they serve as a necessary predecessor to baked brick technology that would basically serve as the next step in humanity's ability to take essentially mud and remake it as solid earth for our own purposes. And how fitting too that this occurred in the shadows of the Ziggorots holy mountains constructed by human ingenuity.
Now, from here I wanted to talk about one specific example of amazing mud based construction practices that still exists in the world today, and that is the example of the mud built skyscrapers of the city of Shibam. So I was reading about this number of sources. One of the main ones out site is an entry in the Encyclopedia of Architectural and Engineering Feats edited by Donald Longmead and Christine Garneault, published in two thousand and one. So the city of Shibam is located in modern day Yemen. It is situated on top of a rock spur at the southern tip of the Ruballkhali Desert of the Arabian Peninsula and the Rublkali. That name means empty quarter. This is an area of approximately one thousand by five hundred kilometers covered in sand dunes, with relatively little human habitation and plant and animal life compared to other areas. It is a hyper arid desert of windswept dunes of sand. So this is near the southern end of that area sort of where it's transitioning into other sort of ecoregions. Many of the buildings that still stand in the city of Shabam today date back to the sixteenth century, though the settlement itself is older. Several sources I was looking at said it went back to the third century CE. The population of the city in the modern era is roughly seven thousand, and most of these people live in these mud brick high rise houses. There are more than five hundred of these structures inside the city walls. I've seen vastly conflicting estimates on the height of the tallest ones. The Encyclopedia entry I just cited says that some of them are up to twelve stories tall. Other sources say the tallest are more like seven stories. I don't know what accounts for that difference, but I bet it depends on how you're counting the stories. Maybe its height versus the actual number of occupied floors, because I think within those buildings the floors are actually quite tall, like the ceilings are high, and there will be multiple levels of windows within a single floor of the building.
That would make sense too, based on some of the the design parameters that are that are common with with with with this sort of climate and the sort of construction material like we referenced earlier.
Right, because you want a lot of windows situated high up so that as hot air rises, it can flow out through those windows. So you get high ceilings, windows up near the ceiling above where the people are walking around.
Now, I think people should if it's safe to do so, you know, not if you're driving the car, obviously, but you should look up images of this because when we say mud rick high rises, or you hear a description like the Manhattan of the desert, which I've seen, you might you might not fully believe it, but because it is very almost unreal to behold. But yes, it does look essentially like parts of Manhattan in terms of the scope of the buildings and the height of the buildings, and the modernity of the buildings, you know, and there's sort of basic shape and design. This does not look like a like like some sort of you know, archaic city. It looks at once modern and yet you can tell there's something about the building materials that is different. So this is a remarkable city that is rising up out of the desert here.
Some sources have identified these as the world's oldest skyscrapers. I don't know how you make the cut for skyscraper, but they are very old buildings and very tall for their construction materials. So they are made of mud bricks, and yeah, you mentioned the sort of nickname used in some Western media, the Manhattan of the desert. As far as I know, the city of Shibam was first called that in the nineteen thirties. I think that it goes back to the British explorer Freya Stark who called it that. And speaking of how the city was described in Western media in the nineteen thirties, I found an article in an old issue of Popular Mechanics from nineteen thirty six called MUDs sky scrapers of desert built long before the log cabin. So it's just a little paragraph, but I wanted to read this because I thought it was funny. So it First the caption on the photo says centuries old city of Shibam in Southern Arabia is a cluster of sun hardened mud skyscrapers that have withstood tests of time and weather. And then the body text says, mud skyscrapers that were hundreds of years old when log cabins began to dot the American wilderness still stand in the ancient city of Shabam in Southern Arabia. The modern steel skyscraper is only fifty years old. Shabomb was a thriving city of tall buildings in the time of the Queen of Sheba, and still is a busy desert metropolis today, so constructed as to withstand the raids of hostile Arab tribesmen, with the windows high above the ground. The Shabam skyscrapers were of mud mixed with straw and maize, dried and hardened by the desert sun. And then directly under that there's another headline that says insects killed by vaporizer heated electrically. But so, as Rob said, if you're able to look up images of the city of Shabam, you should because it's amazing looking. But if you can't, one thing you should understand is that the city itself has a notably small and tidy horizontal footprint. It is about half a square kilometer stretching up instead of out. And when it was recognized by UNESCO's World Heritage List in the nineteen eighties I think it was nineteen eighty two, it was described as quote one of the oldest and best examples of urban planning based on the principle of vertical construction. Now, Rob, I'm about to divulge something of great relevance to you. Personally, I know you love a skybridge. Well, A lot of the mud built high rises in Shabam are linked by upper floor floating corridors. Skybridges may out of mud. So I attached some photos here for you to look at. It looks, at least at least some of the photos I could find, it looks like the skybridges are not covered on top. I don't know if they're all like that or if it's just some of them, but in some of these photos it's like a walkway connecting the upper floors of these buildings that has a bottom, of course, and then it has walls rising up on the sides, but not a roof.
Wow, this is amazing. Yes, I had no idea, but here they are. Yeah, the mud brick skybridges, I'll take it.
So from what I've read, the design of the city with its mud walls all around it also, as I said, it has walls surrounding the city that are also made of mud brick. The design of the city, with the walls, the high rises and the skybridges, is in large part defensive in nature. The city was built to defend itself against marauders. Now why, like, what would make this city in particular a target for such attacks. According to some sources, it may have a lot to do with Frankensnse and the Frankensense trade. Frankinson's traders used to have routes that cross the Rubl Khali desert, and Shibam was a hub along one of those caravan routes. So there was a lot of Frankensense trade and as a result, a decent amount of wealth associated with that. Now, Rob as you mentioned, mud based buildings are great and that they have many wonderful properties, but they do need frequent upkeep. The walls have to be replastered on an ongoing basis to counteract erosion damage from wind and rain, and they also have to be built with the limitations of their construction materials in mind. So the mud high rises here they tend to have thicker walls near the bottom that become thinner as the stories go up. So the buildings kind of taper inward as they go up higher, and this is to reduce the weight load from higher floors pressing down on the bricks below, because again the walls are partially load bearing, though there are also some internal posts like timber posts that help bear the weight of the building as well. I was kind of surprised to learn that many of the houses here are actually occupied only by a single family. So often the family will live on the upper floors of the building, and then the lower floors are places that are traditionally used for storage of food, like grain storage and for livestock.
That's fascinating, and I guess it would make sense too that you'd want to live on those upper floors because you would get more ventilation and so forth.
Now, Shbam lies in a valley at the confluence of several waddies. A waddy is a ravine or a river channel in the desert that is dry most of the time, but then floods with water during the rainy season, and as often have in desert environments, it can be very dry and then suddenly extremely wet when the rain comes. You know, so the flood comes in, and that can be very dangerous to human settlements, especially settlements made out of mud brick. Because of the placement at the convergence of these waddies, Shabam is vulnerable to flooding and has suffered catastrophic flooding damage at various points in history. Such as in fifteen thirty two, that's when a lot of the city had to be rebuilt. And why that's you know, as far back as most of the skyscrapers there today date. Now, why would you build high rises out of mud here instead of just more you know, regular low lying dwellings. Well. The entry in the Encyclopedia of Architectural and Engineering Feats identifies several reasons for the vertical expansion. One is because of the area's proneness to flooding. The city is situated up, as I said on kind of a rockspur so it's raised up above the floor of the valley, but not raised up enough to totally avoid flood damage, and floods can threaten it. So one is protection from flooding. Another is preservation of horizontal acreage around the city for agriculture, because there are date palm groves all around, and so expanding the footprint of the city would essentially cut into the farmland around it.
This detail makes for some really beautiful photos though, because you see those brilliant green date palms all around the outside walls of the city.
Yes. Another reason is the desire to gather families in a single building I guess this means like even large families. And then finally to squeeze more of the city inside the protective perimeter wall, which again was to defend against raiders who might want to attack the city for its wealth associated with the Frankinson's trade. Now we've already covered how mud bricks are made, but how are these skyscrapers in particular are put together. Well, they are made out of mud bricks as far as I can tell, you know, based on the normal method. So these would be mud reinforced with straw baked in the sun, which is stuccoed over on the outside of the buildings with a plaster made out of clay and chopped straw. And then this is all placed upon a stone foundation. As I said, the mud brick walls tend to taper inward and become thinner as they go up, because again the walls are partially load bearing. The buildings reach heights of forty meters or one hundred and thirty feet, and the walls of the ground floor are generally between one point three and two meters thick, so that's like four to six feet thick. There's a lot of it just seems to be a lot of energy efficiency in mind in the construction of the city because they have all these properties. But also like they have the sky bridges I mentioned, and that is to allow neighbors to visit one another without having to go up and down the stairs, you know, go up and down, wasting energy going that way. But then also the upper floors have this external white stucco to help reflect solar radiation and help keep them cool.
I love I love this detail about the skybridge because this, like this lines up with the basic rationale for skybridges in the age of skyscrapers, and this sort of you know, forward thinking futuristic idea that like, well, life is going to be up there now and we need to move around up there building to building, And this is an example of it not really being a thoroughly futuristic idea at all, Like it's it's ultimately a much older, even ancient idea at least in places where you had tall buildings like this.
Or maybe you could say it has been part of a smart, progressive technological framework for ages.
Yeah, yeah, I think so, because I imagine imagine like coming to this city centuries ago, you know, and just how modern and advanced, it would be like this was like the blade Runner city of the day.
Now a lot of the city's architecture centers around helping to deal with extreme heat. So one advantage of having tall buildings close together is that it really helps to provide shade within the city. Buildings also have a lot of windows to aid in ventilation, especially near the top, letting hot air out. But they also like the doors in these buildings, many of them are carved wooden doors that will have like these beautiful geometric patterns carved into them, but they will have openings in the wood of the doors again to allow ventilation, you know, natural airflow through. And also in the city. I was watching one video documentary about it that showed the city still having some very old school wooden locks, so like locks on doors that you would open by having a wooden paddle that has a particular arrangement of pegs poking up off of it, So you can reach the wooden paddle into the lock hole and you press it up and if it has the right arrangement of pegs, it lifts the what do they call the lifts the little tumblers, I guess, and then the lock opens Some buildings in the city also have wooden mashrabias, which are if you don't know what that is, it's sort of like a wooden, enclosed but ventilated deck area sort of, I don't know the correct way to describe it. Look it up, look up pictures of them. There are these beautiful external features that you see on a lot of buildings throughout the Islamic world.
You know, coming back to what you said earlier about the setbacks in the design, the idea that you know, they taper inward and there's kind of a terracing as they go up. And of course this applies to more than just mud brick buildings, but you know, thicker at the bottom less mass towards the top. You know. This makes me think of setbacks in like a modern city environment like New York City, where even when you get to the point where you don't need the setbacks from a structural standpoint, setbacks end up being desired. You know, well for I guess a couple of reasons. One just esthetically, but also uh, you put these setback laws in place because you don't want to create the just like depths of shadow where the sun never shines, you know, you want there to be sort of more open sky in these these ravines between the skyscrapers. And yet also, you know you touched on with with this city that you know, to a certain extent, those wells of shadow are also desired because you want to create to create some additional escape from the overbearing power of the sun.
Yeah, that's right. So I guess again there are trade offs there. As you know, building building materials and architecture really is a story of trade offs, isn't it. Yeah. I don't know if that's a banal observation, I just it just occurred to me.
Well, I think the banal becomes the spectacular when you start looking at examples like this that turn our understanding of skyscrapers and modern urban environments on their head by placing them in in a much older setting and a different environment than we're used to contending with. So it's yeah, such a fascinating model to look at.
Now. One last thing is I was reading about some threats to this beautiful architectural heritage recently due to weather and especially due to conflict in Yemen, leading to difficulty and performing the upkeep necessary to keep these buildings standing and all that there was apparently a tropical cyclone in two thousand and eight that caused a lot of flooding and damage to buildings in Shabam. And also I think there are some other settlements in the same region that have some similar construction and architecture in them that are also under threat due to flooding and weather and just lack of ability to perform the necessary upkeep. So I know there are some restoration and maintenance projects that are underway. I think UNESCO might be involved in something going on there, But it would be a shame to see this beautiful and ingenious architectural tradition, which is in a way it's a tradition that's ongoing because of the upkeep you always have to do to keep these buildings alive to see that go away.
So yeah, now we also want to stress though that of course, this is just one of the phenomenal examples of mud brick based architecture you can find throughout the world. Like I said earlier, structures made out of mud brick are still common throughout North Africa and beyond North Africa, but this one really kind of stood out to us as something worth highlighting and just showing like what is and was possible with mud brick. So, anyway you have a particular favorite, or if you've visited a city or an archaeological site that features impressive mud brick construction, right in, let us know. We'd love to hear from you and we can talk about it in a future listener mail episode. Now, as for mud as a whole, our multi part look at Mud, I think we're going to go at least one more episode here. We're going to come back a little bit too, mud and warfare. We're going to talk about mud volcanoes and who knows what else. There may be another mud angle that we don't even know about yet because it is yet to emerge through our research, so make sure you tune in for that on Tuesday. I mangine a reminder that our core episodes of Stuff to Blil Your Mind published on Tuesdays and Thursdays, and the Stuff to Bulil your Mind podcast feed. We have Let's see listener mails on Mondays, we have short form artifactor Monster Fact on Wednesdays, and on Fridays, we set aside most serious concerns to just talk about a strange movie on Weird House Cinema.
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