Concrete Built The Modern World. Now It’s Destroying It.

ZÜRICH — In the aftermath of World War II, the leaders of Switzerland decided that the country needed to urgently modernize, and concluded that a remote and picturesque valley high in the Alps could be developed for hydropower. Nearly 350 square miles of snow and ice covered the mountains there, and much of it turned to liquid in the spring and summer, a force of water that, if harnessed correctly, could turn turbines and create electricity. And so a plan was hatched to conquer this “white coal” by building the tallest concrete gravity dam the world had ever seen: the Grande Dixence. At nearly 1,000 feet high, it’d surpass the Hoover Dam and be only slightly shorter than the Empire State Building, then the tallest building in the world.

From 1951 onwards, around 3,000 geologists, hydrologists, surveyors, guides and laborers, outfitted with an assemblage of trucks, diggers, dumpsters and drills, advanced like an army into a mostly untouched area of the Alps. To paraphrase Leo Marx: The machines had entered the garden. 

Up there, the workers were met with freezing temperatures that seared the chest and burst the lips, a blazing sun that burned the skin, and a constant threat of avalanches. They lacked waterproof clothing and lived in makeshift shacks, at least until social services forced the construction of an accommodation block that they nicknamed “the Ritz.” The fine dust of pulverized rock coated their lungs, developing, for some, into a slow and deadly disease called silicosis. The site had its own chaplain, Pastor Pache, who was available to counsel the men about their confrontations with nature and death. 

Ultimately, the job these men performed, more than anything else, was pouring concrete, and at a nearly unimaginable scale: more than 200 million cubic feet of it, just about enough to build a wall five feet high and four inches wide around the equator. Cableways carried an endless procession of 880-pound buckets of cement (a primary ingredient in concrete alongside sand, gravel and water) up and down the mountains at a pace of 220 tons each hour. 

For more than a decade, through snow and rain and fog, the workers poured that thick grey mixture day after day after day, and gradually a monolith began to rise between the mountains.

One of the workers was 23-year-old Jean-Luc Godard, who would go on to become one of the most influential filmmakers in the modern era. After sweet-talking his way into a cushy job as a telephone operator, he borrowed a camera and began capturing images of the never-ending flow of concrete. In the film he eventually made (not one of his finest), workers were portrayed like little ants alongside grand machines, and a triumphant soundtrack of classical music played beneath a cheerful voiceover that celebrated the national importance of this monumental construction. Opération Béton, he named it — Operation Concrete — and the construction company bought it off him and rolled it out as an advertisement in cinemas across the nation.

Godard had moved on by the time the dam was completed in 1961. The finished wall weighed 16.5 million tons and held back more than 14 billion cubic feet of water, and the finished complex now generates some 2 billion kWh of power per year and accounts for 20% of Switzerland’s energy storage capacity. A huge crowd gathered at the top to watch workers pour the final load of concrete, clapping and cheering. A mythology of man triumphing over nature spread through documentaries, books and tourist guides. One booklet described it as a “concrete temple enthroned in a mineral universe,” another as akin to the great pyramids of Egypt, except “useful.” It took on a divine air, like a modern cathedral. Raw material from the dam was even trucked to a nearby village to build a futuristic new concrete church. 

It was the beginning of an era of rampant construction in Switzerland. In the 1950s and 60s, the Swiss poured more concrete per capita than any other country; before the century was out they would expand beyond their borders and become globally recognized concrete connoisseurs, building dams in Morocco and Kenya, housing projects in Iran and airports in Saudi Arabia, each with their own cement factories to provide material. But the Swiss were not alone: Across the Global North, concrete mania had taken hold. 

By the mid-1960s, Godard was in Paris making some of the early masterpieces of the French New Wave, but the earlier wondrous optimism he’d felt for concrete was now replaced by a horrified fascination. The modernist utopian dream that the speed and malleability of concrete might solve housing crises, revolutionize cities and birth new ways of living and being was already being shattered by a spiraling capitalist cycle of speculation, construction, deterioration and demolition. 

In “Alphaville” (1965), a tyrannical dystopia, Godard used the newly concreted areas of Paris as a backdrop. Two years later, in the opening scene of “Deux ou trois choses que je sais d’elle,” a wheelbarrow caked in concrete sat on a recently built motorway, surrounded by a deafening cacophony of traffic and construction. Everywhere the camera looked, Paris was full of holes and craters; cranes filled the sky and the new concrete tower blocks were portrayed as monuments of alienation and loneliness. Godard theorized that the city, like his female protagonist, had been forced to prostitute itself just to survive in an era of “progress.” 

Concrete had been poured before World War II, but it was nothing compared to the scale of what was now taking place. In 1900, minerals associated with the production of cement accounted for only 15% of construction material; by the beginning of the 1970s, it was more than 60% and rising rapidly. The American architect Frank Lloyd Wright described the amount of construction afoot as an “amazing avalanche of material.” In Lagos, the arrival of some 20 million tons of imported cement caused a traffic jam of ships that paralyzed the port for almost a year. 

Godard focused so acutely on concrete because its transformation of the Earth’s surface was happening in front of him. But like anything that becomes ubiquitous, now we hardly notice it. Today, like a heartbeat, concrete is rarely acknowledged, even as our lives depend on it. 

Most of humanity now lives in cities made possible by concrete. The majority of buildings, from skyscrapers to social housing, are made of concrete or contain large amounts of it. Even buildings made from steel, stone, brick or timber are almost always resting on concrete foundations and are sometimes masking an unseen concrete frame. Inside, concrete is ceilings and floors. Outside, it is bridges and sidewalks, piers and parking lots, roads and tunnels and airport landing strips and subway systems. It is water pipes, sewers and storm drains. It is electricity: dams and power plants and the foundations of wind turbines. Concrete is the wall between Israel and Palestine and the Berlin Wall and most other walls. It is “almost anything,” wrote the architect Sarah Nichols in an essay this year, “almost anywhere.”

Concrete is modern, yet ancient. There’s a sense in which it was born in the bowels of volcanoes, formulated by the eruptions of the Earth. Around 100 B.C., Romans discovered that volcanic ash from the slopes of Mount Vesuvius could be mixed with lime and wetted to create a cement, to which they added aggregate. Roman concrete was used to build structures like the Pantheon and the Colosseum, original parts of which still stand today. The story goes that their recipe was lost until it was rediscovered in the ancient books of Vitruvius. What seems more likely is that the use of concrete became much rarer, but never completely died, and still circulated via artisanal builders and craftsmen, until engineers and scientists across Europe eventually understood and then industrialized it. 

To make concrete, you need cement. To make cement nowadays, kilns are heated to more than 1,400 degrees Celsius — similar to the temperature inside a volcano. Into the kilns goes a combination of crushed raw materials (mainly limestone and clay). The heat causes a chemical reaction that creates a new product, clinker, which is then ground down to create the grey powder you see in cement bags. This is then mixed with sand, gravel and water to create concrete.

Concrete is now the second-most consumed substance on Earth behind only water. Thirty-three billion tons of it are used each year, making it by far the most abundant human-made material in history. To make all that, we now devour around 4 billion tons of cement each year — more than in the entire first half of the 20th century, and over a billion tons more than the food we eat annually. 

Such a monstrous scale of production has monstrous consequences. Concrete has been like a nuclear bomb in man’s conquest of nature: redirecting great rivers (often away from the communities that had come to rely on them), reducing quarried mountains to mere hills, and contributing to biodiversity loss and mass flooding by effectively sealing large swathes of land in an impermeable grey crust. The other key ingredients all bring their own separate crises, from the destructive sand mining of riverbeds and beaches to the use of almost 2% of the world’s water.

But most significantly, the carbon-intensive nature of cement has been catastrophic for the atmosphere. The kilns used to heat limestone are commonly run on fossil fuels, which produces greenhouse gases, and as it heats up, the limestone itself releases more CO2. Every kilogram of cement created produces more than half a kilogram of CO2. The greenhouse gas emissions of the global aviation industry (2-3%) are dwarfed by those of the cement industry (around 8%). If concrete was a country, it would be the third largest CO2 emitter, behind only the U.S. and China. In Chile, the region that houses most of the cement plants, Quintero, has become so polluted that it was nicknamed “the sacrifice zone.”

Sacrifice is a fitting word for this paradox: On the one hand, we have the destruction wrought by concrete, and on the other is our desperate need for it to exist. It’s been estimated that to keep up with global population growth, we need to build the urban equivalent of another Paris each week, another New York each month. “A lot of people say, ‘Oh, we shouldn’t use concrete. We should be using something else,’” Karen Scrivener, a leading scientist in the race to create lower-carbon concrete, said in 2012. “This is a totally meaningless comment because it is just not physically possible to produce any other material in such large quantities.” Tyler Ley, a professor of civil engineering at Oklahoma State University, told me: “We never complain about water, but producing freshwater has a massive carbon footprint. We think water is essential. Concrete is in that same vein.”

Concrete has become global because it is produced from some of the most abundant materials on Earth, which means it can usually be manufactured locally, almost anywhere. Building a basic concrete structure is usually easier than using other materials like wood or steel. And it’s cheap: Adjusted for inflation, the cost of cement in the U.S. has barely risen since the beginning of the 20th century. These factors mean concrete has been the great emancipator in poorer parts of the world, enabling low-cost construction of housing, schools and hospitals, even in communities neglected by their governments. “Production and consumption of cement alone,” wrote the anthropologist Cristián Simonetti, “is in almost perfect correlation with the World Bank’s development indicators.”

As the climate crisis accelerates and extreme weather events become more common, concrete will be more important than ever: It is waterproof, fireproof, strong enough to withstand powerful winds and will usually be sturdy for a lifetime or more. As seas rise, coastal walls are being built of concrete to protect urban areas — around 14% of the American coastline and 60% of the Chinese coastline is effectively concrete. On the coast of Nigeria, a 5-mile concrete barrier known as “the Great Wall of Lagos” is being constructed to protect the city’s more affluent neighborhoods from coastal erosion.

In architecture, discussions about concrete have become polarized: Talking about it, as the director of the Swiss Architecture Museum said in a panel discussion earlier this year, is like “talk[ing] about vaccination.” The realization of concrete’s destructive nature has fueled a growing movement to use wood instead, specifically what’s called mass timber: panels of wood that are glued and pressed so tightly together that they come close to the strength of concrete. Three years ago, the world’s tallest timber skyscraper, Mjøstårnet, opened in Norway. The Rocket&Tigerli building in Winterthur, Switzerland, will surpass it when it is completed in 2026. There are plans to emulate these approaches around the world, and there is an enthusiasm among architects and urban planners that we may be at the beginning of a new “skyscraper age” for wood similar to the one fueled by the capabilities of concrete.

On one of the 40 islets of the Enewetak Atoll in the Marshall Islands, there is a gigantic concrete dome known as “the Tomb.” Between 1946 and 1958, the U.S. military conducted 67 nuclear tests in the Marshall Islands, dropping the equivalent of about 1.5 Hiroshima bombs per day. A decade later, the Tomb was built to contain 110,000 cubic yards of highly radioactive soil. A few years ago, someone climbed up onto its surface, which sits just above ground level, and spray painted a message: “Nuclear Waste. Property of USA Government. Please Return to Sender.” 

Modern concrete usually lasts around 100 years before it starts to crumble and fall apart. The half-life of plutonium-239, one of the radioactive particles present in the Tomb, is around 24,000 years. There are already cracks around the edges of the Tomb, and toxic waste is seeping into the surrounding soil and ocean.

The mythical power, permanence and strength of concrete — its ability to protect us from what is dirty and dangerous — still lingers in the public imagination: a magic liquid rock that could be poured to create shapes and forms that were possible in no other material. Stone takes nature millions upon millions of years to create, but we do it in a few hours. Mankind, it seems, has harnessed the geological forces of deep time. 

Architects and builders once regarded concrete as permanent, everlasting. “Cement means concrete; concrete means stone; and stone spells eternity, so far as our finite minds can comprehend,” wrote Floyd Parsons in 1924. But, as Vyta Pivo, an assistant professor of architectural and urban history at the University of Michigan, told me over the phone, “Concrete is none of the things we were led to believe it is.” She explained: “Our addiction to concrete is not just a scientific or technological issue, it’s a deeply cultural issue. This idea of concrete as a miracle material was actively pursued by people in positions of power. In the U.S., for example, manufacturers and companies created movies, booklets and magazines. They trained people to go into rural areas and teach people how to work with cement and use concrete in all kinds of daily applications. It was a real education project to teach us how to accept concrete into our everyday environments. So it wasn’t that concrete was necessarily the best or most obvious or cheapest. There were certain actors who made it that way.” 

Throughout the 20th century, as the U.S. expanded its power abroad, a cult of concrete followed. Prior to the American occupation of the Philippines in 1898, not a single bag of cement had ever been shipped there. By 1913, wrote Diana Martinez in her book “Concrete Colonialism,” visitors were describing “Manila’s approaching horizon as a ‘huge mass of concrete.’” Likewise, wrote Pivo, “In Vietnam, concrete was deployed to create a material surface on which U.S. foreign policy unfolded.” 

But modern concrete does not operate on the deep time of rock. Its durability is severely limited. It is restless. “Reinforcement really is the only reason concrete is everywhere today,” said Lucia Allais, an associate professor of architecture at Columbia University. Experiments with reinforced concrete began in the mid-1800s as people sought to mask its weaknesses and make it do things it couldn’t. The reason for this is that concrete has extremely high compressive strength: It’s really difficult to crush. Today’s strongest concretes can withstand pressure of more than 100 megapascals — “about the weight of an African bull elephant balanced on a coin,” as the historian Vaclav Smil put it. But concrete has low tensile strength: It’s easy to pull apart. Steel bars, it turned out, have pretty much the opposite qualities, so rebar (reinforcing bar) became commonly used to create a strengthening skeleton for concrete to be poured around. Almost all of the concrete you see today is reinforced.

“The problem with that is the process of carbonation,” said Allais. “There is carbon dioxide everywhere in the atmosphere, and any time concrete is exposed to carbon dioxide, it permeates its pores.” When the CO2 permeates it triggers a chemical reaction in the concrete that causes the rebar to rust. “The steel expands because it’s rusting. And the concrete cracks and fails. … And what’s especially interesting is that the amount of CO2 in the atmosphere in the last 100 years has greatly expanded, due in no small part to the fact the concrete industry is emitting massive amounts of it into the atmosphere.”

Scientists are trying to figure out how long it takes reinforced concrete to degrade because of carbonation. The average result for a standard structure is 100 years, Allais said. “When you consider that reinforced concrete was invented around 100 years ago,” she went on, “you get this amazing image that the concrete all around the world is beginning to fail.”

There have already been several high-profile fatal accidents with concrete infrastructure, like the Morandi Bridge in Italy that collapsed and killed 43 people in 2018, or Champlain Towers South, a 12-story building in Miami that fell and killed 98 people in 2021. But the rot is widespread: Last year’s Infrastructure Report Card for the U.S. graded much of the country’s concrete infrastructure — roads, dams, airports, stormwater systems, inland waterways — as a D, meaning poor, at-risk and exhibiting significant deterioration. In the U.K., a health minister disclosed to Parliament this year that 34 hospital buildings have concrete roofs that are in danger of sudden collapse. 

We find ourselves on a treadmill of dependency on a material that is slowly deteriorating from the moment it is first poured. While much of the Global South is embarking on a century of construction, the built environment of the Global North is destined for the monumental challenge of maintenance, demolition and, in the worst-case scenario, ruination. 

Demolished concrete buildings will go mostly into landfills. Concrete can, in theory, be recycled, but the process of separating rubble from rebar is expensive and time-consuming, and therefore done on nowhere near the scale to make an impact. Observing landfills in the Lehigh Valley in Pennsylvania, Pivo noticed concrete was being dumped back in the huge craters of old limestone quarries that its production created. Mass deposits of crumbled concrete, academics have suggested, will become the stratigraphic marker of our age: a scar left by the great acceleration that really will last for eternity.

On the evening I arrived in Zürich, I walked past a bistro showing a documentary called “Dead End Concrete,” about concrete’s role in environmental degradation. Materials are really on the mind around here, most likely because of the influence of ETH Zürich, the city’s esteemed public research university. Nicknamed “the M.I.T. of Europe,” ETH is a hotbed for science, technology, engineering and mathematics, and boasts 22 Nobel laureates among its alumni, including Albert Einstein. 

I’d come by train to meet Philippe Block, the head of ETH’s Institute of Technology in Architecture. Block is quick to acknowledge concrete’s problems, but his mantra is “Do concrete right.” “Sustainability is not just about materials,” he said as we walked around one of the campuses. “It’s about what you do with materials. Just saying that concrete is bad and wood is good is just wrong. … In the developing world, we have to provide adequate dwellings, infrastructure and so on. There is no way around it. Now, if we were to build all that in timber — can you even imagine the deforestation and the monocultures required to grow all that wood? The amount of biodiversity destroyed? It would be like palm oil times a thousand. It would be a total disaster.”

There won’t be a single perfect solution to the problem of concrete. One potential advancement is green concrete, which is decarbonized by changing the recipe, production process or longevity. Another is to capture emitted carbon at cement plants and store or reuse it. 

Block is most interested in drastically reducing the sheer amount of it that we pour into our built environment. His research focuses on the ways we can more intelligently design and build. “I want to show that this so-called worst material can be the opposite, if you do it properly.” Thinking of concrete as artificial stone, he claims, can help us recover the lost art forms of the master masons. “And the language of stone,” he said, “is the arch.” 

Block’s early research was focused on heritage architecture — vaulted cathedrals and other historic structures. “Our modern engineering tools are quite inadequate in explaining how safe these buildings are,” he said. Sometimes, he went on, digital engineering models of old buildings concluded that there should be no way they could still be standing, that they should’ve collapsed centuries ago. But there they were, solid, unmoving. Maybe, Block thought, there was something wrong with the models. 

Block was drawn in particular to vaults: self-supporting arched roofs or ceilings, different types of which have recurred in various architectural styles, from the muqarnas vaults across the Islamic world to the Nubian vaults in Sudan and Egypt to Gothic architecture in Europe. He went to visit Kings College Chapel in Cambridge, which was completed in 1515 and boasts a peculiarly English style of vault called a fan vault, because the pattern resembles spread fans. Constructed by the master mason John Wastell, the chapel vaults were designed with a flawless geometry that supported the entire ceiling through compression alone, without any mortar or cement. Staring up at that ceiling, both beautifully simple yet overwhelmingly complex, you feel like you’re beneath something organic, like a spider’s web. William Wordsworth called it a “glorious Work of fine intelligence”: “Where light and shade repose, where music dwells / Lingering — and wandering on as loth to die; / Like thoughts whose very sweetness yieldeth proof / That they were born for immortality.”

Block went for a walk on top of the vaults. “In thickness-to-span ratio, they were proportionally as thin as an eggshell. They were so thin I could feel them vibrating. When I jumped, I felt them bounce. And yet they were still strong and standing. When you have an experience like this, and really feel how exceptionally thin this totally unreinforced structure is, it really motivates you. You realize: Damn, we have forgotten something. We have forgotten this knowledge.” 

Block’s research group started to investigate various styles of vaults, and crunched their logic to create bridges, pavilions and shell structures that were exhibited around the world. He wanted to show the possibility of what he calls “strength through geometry.” But after being provoked by a colleague to demonstrate how these discoveries and ideas solved the major challenges faced by modern construction, Block’s team decided to focus on one of the most banal yet important structural elements of a building: floors. 

“We need to talk about floors,” he told me. To combat sprawl, Block acknowledges, we have to build a little higher. But for a mid-rise concrete building, say 20-40 stories, 75% of its mass is in the structure, which exists mainly to keep the building up, and nearly half the mass of the structure is floor. “In other words,” Block said, “providing a flat and horizontal surface for people to walk on is super materially intensive.” An estimated 2 trillion square feet of floor, most of which will consist of thick slabs of reinforced concrete, is expected be constructed all over the world between now and 2050.

After 10 years of research and development, Block and his team devised what they call the Rippmann Floor System (RFS). It is an unreinforced concrete panel that is designed to redistribute the forces of compression around the floor using roughly the same logic as vaults. The final version of the panel is a secret for now, but Block showed me a small prototype. It was rectangular and composed of five interlocking pieces, and to my eye looked like a simplified version of the vaults you might see in a cathedral. 

Block is sometimes criticized for his ties to the cement industry — he is on the board at Holcim, Switzerland’s biggest cement company. But he is not apologetic about it. He hopes those relationships can steer architecture in a more sustainable direction. His floor panels would reduce the amount of concrete and steel used in the floors of an average high-rise by around 65% and 80% respectively, according to his team’s calculations. For an average 25-story concrete building, that would mean 1,200 concrete trucks that don’t need to come to the construction site. With no rebar, RFS doesn’t carbonate and deteriorate in the same way as common reinforced concrete. And because the panels are dry-assembled and held in place just by compression, they can be disassembled and reused when the building reaches the end of its life. The RFS floor is already being planned for several multi-story building projects, including one in Brussels and another in Zug.

One challenge Block faces is convincing people that don’t have a rich understanding of masonry and geometry that such a lightweight and fragile-looking floor panel, held in place without any binder, is actually as safe as a thick slab of concrete. Instinctively for most of us, “light” seems like “weak.” 

“We’re so used to thinking: If we add material, it will make things stronger,” Block said. “But geometry is so much more effective at giving you strength and structural stability.” He likes to give famous examples, like Grand Central Oyster Bar in New York, the delicate tile ceiling of which supports the vast Vanderbilt Hall above. Proportionally, Block said, those vaulted ceilings are even thinner than his floor plates. 

In the poorer suburbs of Inhambane in Mozambique, people are making blocks. Men, women, employed, unemployed — everyone is making blocks. Buy cement, mix it, make blocks, pile them high, build a concrete house. 

For some, this takes months; for others, years. The price of a bag of cement has become as colloquial as a beer or a pack of cigarettes. As the anthropologist and sociologist Julie Soleil Archambault wrote, people in Inhambane even think in terms of cement, assessing jobs in terms of how many bags they’ll be able to purchase with their wages. A joke in bars, she noted, is that a slow drinker must be making blocks. 

After poured blocks have set, they then must be cured with water to prevent them from cracking. Around neighborhoods, you’ll see people watering their blocks with a hose as if they were flowers. In 2016, one of the most popular songs in the city — “Uma cerveja, um bloco” (“One beer, one block”) by DJ Ardiles — reminds young people that they could be making concrete instead of drinking. Making blocks, Archambault wrote, isn’t just “making blocks” — “it’s a euphemism for forward-thinking.”

Concrete was once viewed as a colonial material in Mozambique. During Portuguese rule, which only ended in 1975, the capital was divided between the “City of Cement” populated by “colonial bourgeoisie” and filled with high rises, apartment blocks and the state apparatus, and the “City of Reeds” of the suburbs, where a largely black Mozambican population lived. The colonial regime prohibited people in the suburbs from building their houses out of anything other than reed, wood or zinc — concrete was banned. That way, wrote David Morton in his book “Age of Concrete,” precarious neighborhoods “could be easily demolished to make way for future expansions of the City of Cement.” 

No longer viewed as colonial, concrete in Mozambique has now become symbolic of urbanization, success and — importantly in a place plagued by extreme weather exacerbated by the climate crisis — safety. This is part of a trend across the continent: Africa is the fastest-growing cement market in the world. It’s the continent’s “new oil,” Bloomberg called it. The continent’s richest man, Aliko Dangote, runs its biggest domestic cement company. Sub-Saharan Africa is projected to contribute more than half of the global population increase between now and 2050. There will be 120 cities of more than 1 million people, including several megacities. Homes will be built, roads will be built, infrastructure will be built. Concrete will likely need to be poured on a scale orders of magnitude greater than it was in the West in the last century. “In Europe, very few people know how to pour concrete,” the geographer Armelle Choplin said in an interview. “In Africa, everyone does.” 

Some observers worry that concrete’s spread across the continent has eroded age-old artisanal craftsmanship and the use of local and more sustainable materials like mud, clay and wood. “Concrete in construction is quicker, uses less manpower and requires fewer workers involved in artisanal trades,” said Ola Uduku, a British-Nigerian architect and the head of the University of Liverpool’s School of Architecture. Skilled artisans, she told me, are becoming harder and harder to find. 

In response to this, some architects, primarily based in or originating from West Africa, have tried to challenge the rise of concrete by championing local knowledge and resources. Diébédo Francis Kéré’s elegant mud constructions — including clinics and schools — made him the first African architect to win the Pritzker Prize in 2022. There are many others emerging, like Clara Sawadogo in Burkina Faso, Mariam Kamara in Niger and Nzinga Mboup in Senegal. Their styles are radically different, but their general principle is the same: to eschew concrete as a universal solution in favor of what’s local and traditional — often mud, clay, stone or wood. These materials, they say, better suit the extreme and fluctuating conditions of their regional climates.

“The reality is something different,” Uduku cautioned. “In terms of the actual construction of low-cost housing in townships, people are still using cement blocks.” Concrete, like it always has been, is cheap and growing ever more universal.

“There are some things that will always need concrete,” Uduku concluded. “But for the poorest parts of Africa, we need to be looking at our local materials. We’re still locked into a system that may have been fantastic in the 50s and 60s, but now we know about the maintenance concrete needs over time — and its role in the climate crisis. It just can’t be the everyday material anymore.”

Before I left Block in Zürich, I asked him what he thought of the Grande Dixence dam. He’d never heard of it. Block was born in Belgium, so being unaware of Switzerland’s biggest and most productive dam was excusable. But it felt indicative of how the gigantic concrete infrastructure of our lives can play such a hidden and secretive role. 

I decided to go see it for myself. I boarded a train headed south, and 24 hours later found myself on a public bus, empty aside from myself and the driver, hurtling around stomach-turning hairpin bends inches away from precipitous drops, ascending into the Alps. The dam and the road leading to it were already closed for the winter, so I got off the bus at the last possible stop, in a small village called Mâche, and began to walk. 

The guides I’d read had warned of challenging conditions so late in the year, recommending snowshoes and checking for avalanche warnings. But the weather was sunny and clear and unusually warm. Switzerland had experienced one of its hottest years on record; its glaciers had lost 6% of their volume due to melting, triple the amount usually seen in extreme years. The Alps in general are expected to lose 80% or more of their current frozen mass by the end of this century. 

Pine and spruce towered around me and cobwebs hung in the air, so thin that the pine needles caught in them appeared to be levitating. I paused at any sound from among the trees, hoping to see the ibex that are common to this area. But I saw none — just a lonely donkey in a fenced-off field.

At around 6,000 feet, the temperature finally began to dip, the leaves crunching frostily beneath my boots. I thought about the 10 cold winters the dam builders had endured, and the sheer hubris of even embarking on the construction of such a gigantic thing in this terrain. Then the forest ended and I was on a mountainside, high above a valley. Across it, I could see the dam; a perfectly straight horizontal line in a jagged, chaotic landscape. 

I’d expected to be impressed, to be struck by the techno-industrial sublime of a gargantuan monolith. But straddled between two enormous snow-capped mountains, it looked exceptionally small, and I couldn’t help but feel underwhelmed.