In Yemen, there's a city full of 500 year old skyscrapers made of mud

Shibam, Yemen's "mudbrick Manhattan". Image: Jialiang Gao/peace-on-earth.org/Wikimedia Commons.

Deep in Yemen’s most remote valley lies the city of Shibam. Surrounded by palm groves, and flanked by the steep cliffs leading up to the Yemeni highland on both sides, the city of 2,000 inhabitants hardly seems impressive. Just a handful of high-rise residential buildings, not so different from the Soviet-style blocks found across the Arab world.

Yet  these buildings don’t date from the 20th century, or even the late 19th century. They were built almost five centuries ago, and have remained largely unchanged since.


On a dustless day, the white finish of its walls can be seen from miles away. The city, one of the few to be designated a UNESCO World Heritage site in its entirety, appears to rise from the plains. Its 500 houses reach an astounding 100 feet in height, almost as high as Chicago’s  first skyscrapers. Perhaps most remarkable of all is the fact that the city was built using nothing but mud.

From a historical point of view, this is an incredible piece of engineering. But does the city also hold the key to a more sustainable architecture? Salma Damluji, the world’s foremost expert on Arabia’s traditional architecture, thinks the city’s use of mudbrick – bricks that have been dried in the sun rather than fired – is a key technique developed to cope with challenges posed by the harsh climate.

A close up of the "skyscrapers". Image: Aiman Titi/Wikimedia Commons.

Mudbrick has a higher heat capacity and lower conductivity than concrete, which means it slows the rate at which the temperature within the building changes. It’s also cheap to produce - labour costs are the only real costs involved - and it’s eco-friendly. Not only does the production of sun-dried bricks involve no polluting emissions, the bricks are also reusable.

And, unlike fired bricks, the physical structure of dried bricks does not change during the drying process. Without its white protective layer, a wet brick simply becomes mud.

In Shibam, climatic considerations manifest themselves in more than just the building material. Wooden windows provide privacy, refract glare and promote air circulation with their low placement, and small ventilation holes near the ceiling. Narrow streets and open plazas further enhance this air circulation on a city level. Thus, the architecture of Shibam reveals a complete approach to urban planning, fine-tuned to the city’s climate and social structure.


Although Shibam’s skyline probably forms its pinnacle, mudbrick architecture is widespread in the Middle East. One of its greatest champions was the Egyptian architect and intellectual Hassan Fathy (1900 – 1989), whose architectural philosophy took great inspiration from the socialist politics of Egypt’s anti-colonial hero: Gamal Abdel Nasser.

James Steele, in his biography of the architect, writes that, “On the one hand, Fathy respected and admired European traditions, while on the other hand he resented them as part of a colonial legacy that had threatened Egypt’s identity.”

Spurred on by discomfort with European models of architecture and urban planning, Fathy researched a wide range of architectural traditions native to Egypt. Though he was greatly impressed by both Pharaonic and Islamic monumental architecture, he was more directly influenced by the vernacular architecture of rural Nubia, an area covering the south of Egypt and the north of Sudan.

It was in Nubia where he first encountered mudbrick. “Once convinced of the long history, durability and cultural applicability of mudbrick, as well as its low cost and environmental advantages,” Steele writes, “Fathy saw no reason why it should not be used on a wider scale.”

Towards the end of his life, he was widely recognised for his development of an architectural philosophy that integrated modern technology with the demands of local culture and nature, winning the Aga Khan Award for Architecture in 1980.

And yet it appears that his work failed to make a lasting impact on architecture in the Middle East. No large scale projects involving traditional building methods exist, and even Shibam is under threat.

While decades of political instability and the current war between Houthi rebels and the Saudi-backed government forces have largely passed by the remote valley, Shibam’s architecture has been in decline since the nationalisation of many of its buildings. Although the buildings are rented out to their original owners, a lack of ownership has made their inhabitants reluctant to invest in the considerable maintenance costs. Without regular maintenance, crucial experience with traditional building methods risks being lost forever.

In close up. Image: Jialiang Gao/peace-on-earth.org/Wikimedia Commons.

And local tradition is crucial. When Oxfordshire organic farmers Lutfi and Ruby Radwan, inspired by the mud brick architecture of Saudi Arabia and Senegal, built Willowbrook Farm, they decided to use similarly eco-friendly methods. However, Britain’s climate is, unsurprisingly, not quite dry enough for sundried bricks.

“Instead, we built using the traditional British method of mixing the cob and building up directly in a continuous lump,” Lutfi says. “We admire Hassan Fathy’s work, but it didn’t influence us greatly. More importantly I had visited a number of mud buildings in Britain to see how local issues were dealt with.”

“Mudbrick architecture is more sustainable and cheaper if one factors in the environmental costs,” he continues. “Materials and labour can usually be sourced locally, so it benefits a local economy rather than relying on inputs from outside, which also affects energy costs involved in transportation.

"Plus, its environmental impact is minimal. These traditional methods are certainly a viable alternative to less environmentally sustainable modern methods.”

Sustainable, local architecture. With a shortage of 3.5m affordable homes reported in the Middle East and North Africa, perhaps an affordable, durable and eco-friendly solution lies in the traditions of a forgotten Yemeni valley.

 
 
 
 

What Citymapper’s business plan tells us about the future of Smart Cities

Some buses. Image: David Howard/Wikimedia Commons.

In late September, transport planning app Citymapper announced that it had accumulated £22m in losses, nearly doubling its total loss since the start of 2019. 

Like Uber and Lyft, Citymapper survives on investment funding rounds, hoping to stay around long enough to secure a monopoly. Since the start of 2019, the firm’s main tool for establishing that monopoly has been the “Citymapper Pass”, an attempt to undercut Transport for London’s Oyster Card. 

The Pass was teased early in the year and then rolled out in the spring, promising unlimited travel in zones 1-2 for £31 a week – cheaper than the TfL rate of £35.10. In effect, that means Citymapper itself is paying the difference for users to ride in zones 1-2. The firm is basically subsidising its customers’ travel on TfL in the hopes of getting people hooked on its app. 

So what's the company’s gameplan? After a painful, two-year long attempt at a joint minibus and taxi service – known variously as Smartbus, SmartRide, and Ride – Citymapper killed off its plans at a bus fleet in July. Instead of brick and mortar, it’s taken a gamble on their mobile mapping service with Pass. It operates as a subscription-based prepaid mobile wallet, which is used in the app (or as a contactless card) and operates as a financial service through MasterCard. Crucially, the service offers fully integrated, unlimited travel, which gives the company vital information about how people are actually moving and travelling in the city.

“What Citymapper is doing is offering a door-to-door view of commuter journeys,” says King’s College London lecturer Jonathan Reades, who researches smart cities and the Oyster card. 

TfL can only glean so much data from your taps in and out, a fact which has been frustrating for smart city researchers studying transit data, as well as companies trying to make use of that data. “Neither Uber nor TfL know what you do once you leave their system. But Citymapper does, because it’s not tied to any one system and – because of geolocation and your search – it knows your real origin and destination.” 

In other words, linking ticketing directly with a mapping service means the company can get data not only about where riders hop on and off the tube, but also how they're planning their route, whether they follow that plan, and what their final destination is. The app is paying to discount users’ fares in order to gain more data.

Door-to-door destinations gives a lot more detailed information about a rider’s profile as well: “Citymapper can see that you’re also looking at high-profile restaurant as destinations, live in an address on a swanky street in Hammersmith, and regularly travel to the City.” Citymapper can gain insights into what kind of people are travelling, where they hang out, and how they cluster in transit systems. 

And on top of finding out data about how users move in a city, Citymapper is also gaining financial data about users through ticketing, which reflects a wider trend of tech companies entering into the financial services market – like Apple’s recent foray into the credit card business with Apple Card. Citymapper is willing to take a massive hit because the data related to how people actually travel, and how they spend their money, can do a lot more for them than help the company run a minibus service: by financialising its mapping service, it’s getting actual ticketing data that Google Maps doesn’t have, while simultaneously helping to build a routing platform that users never really have to leave


The integrated transit app, complete with ticket data, lets Citymapper get a sense of flows and transit corridors. As the Guardian points out, this gives Citymapper a lot of leverage to negotiate with smaller transit providers – scooter services, for example – who want to partner with it down the line. 

“You can start to look at ‘up-sell’ and ‘cross-sell’ opportunities,” explain Reades. “If they see that a particular journey or modal mix is attractive then they are in a position to act on that with their various mobility offerings or to sell that knowledge to others. 

“They might sell locational insights to retailers or network operators,” he goes on. “If you put a scooter bay here then we think that will be well-used since our data indicates X; or if you put a store here then you’ll be capturing more of that desirable scooter demographic.” With the rise of electric rideables, Citymapper can position itself as a platform operator that holds the key to user data – acting a lot like TfL, but for startup scooter companies and car-sharing companies.

The app’s origins tell us a lot about the direction of its monetisation strategy. Originally conceived as “Busmapper”, the app used publicly available transit data as the base for its own datasets, privileging transit data over Google Maps’ focus on walking and driving.  From there it was able to hone in on user data and extract that information to build a more efficient picture of the transit system. By collecting more data, it has better grounds for selling that for urban planning purposes, whether to government or elsewhere.

This kind of data-centred planning is what makes smart cities possible. It’s only become appealing to civic governments, Reades explains, since civic government has become more constrained by funding. “The reason its gaining traction with policy-makers is because the constraints of austerity mean that they’re trying to do more with less. They use data to measure more efficient services.”  

The question now is whether Citymapper’s plan to lure riders away from the Oyster card will be successful in the long term. Consolidated routing and ticketing data is likely only the first step. It may be too early to tell how it will affect public agencies like TfL – but right now Citymapper is establishing itself as a ticketing service - gaining valuable urban data, financialising its app, and running up those losses in the process.

When approached for comment, Citymapper claimed that Pass is not losing money but that it is a “growth startup which is developing its revenue streams”. The company stated that they have never sold data, but “regularly engage with transport authorities around the world to help improve open data and their systems”

Josh Gabert-Doyon tweets as @JoshGD.