How Do Buildings Last 2,000 Years?

With concrete that "self-heals"...

Read time: 5 minutes

This building is no less than 1,896 years old…

Rome’s Pantheon has been used continuously since it was built around 128 AD. The Aqueduct of Segovia carried water from antiquity until the 1970s. 

What do these structures have in common? They’re Roman, they’re stunning examples of ancient craftsmanship, and they’ve lasted far longer than anything else.

But how do Roman buildings remain standing for millennia? Why aren’t there more of them left?

And what can they teach us about construction — and culture — today?

Update!

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You’ll get behind-the-scenes, deep-dives and interviews with some truly great minds — in the world of art, architecture, academia and much more.

Last week, I spoke to the personal architect of King Charles. This week: Florence, the Medici, and the craziest murder plot of the Millennium…

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Self-Healing Buildings

The Pantheon’s majestic dome and oculus

We don’t often associate Roman architecture with concrete. The cheap, industrially-available form of concrete is completely modern, but the Romans used their own version of it to build durable yet intricate structures.

While modern-day concrete crumbles in a few decades — and looks uglier with each passing year — Roman concrete structures have remained intact and beautiful for thousands of years.

How did they manage that? Incredibly, it wasn't until some research by MIT in 2022 that we came to truly understand how…

Ancient builders cleverly chose the most reactive form of limestone to cement their concrete mixture. When added to concrete, the limestone triggers chemical reactions that form deposits of calcium carbonate within the material. When water reacts with these “lime clasts,” it causes the materials to recrystallize and strengthen. In other words, as soon as a crack develops in the concrete, all it takes is a good rain shower — and the concrete chemically repairs itself

Calcium carbonate “lime clasts” in the concrete

After the Roman Empire fell, the recipe was lost. Only in the 15th century, when an ancient manuscript resurfaced with notes on the recipe, was the race to "re-invent" concrete reignited.

Even today, our concrete still hasn't really caught up. It might be stronger, especially when reinforced by steel bars, but it's not as evergreen — those bars tend to corrode over time.

This concrete formula is the secret behind one of the ancient world’s greatest mysteries: the great dome of the Pantheon. The temple’s iconic dome has a 42-foot diameter, making it the largest unreinforced concrete dome ever built. Not even modern construction methods have been able to mimic it, much less its 2,000-year lifespan.

The discovery is changing the way that modern builders use concrete, but it’s also a mesmerizing reflection on culture. It turns out that the relics of ancient times aren’t just crumbling away in the sands of time, but actively healing themselves — they’re more like living bones than inanimate objects.

Culture, too, acts similarly — when properly preserved, it doesn’t simply wear away over time. Rather, its bones keep repairing themselves, making it stronger than ever.

Aqueducts and Arches

There is no cement holding these stones together, only gravity

Rome’s greatest infrastructural achievement may well have been its aqueducts. With over 200 of them built across the empire, including over 500 miles of aqueducts within the city of Rome itself, it’s hard to say what’s more impressive: the first mass-scale system of running water, or the fact that many of these architectural marvels are still standing today.

The great aqueduct of Segovia, Spain, is one of the most impressive remnants of the ancient world. It transported water over 10 miles, and was still carrying water up until 1973, shortly before it was named a UNESCO World Heritage Site.

What’s most impressive, though, is that this aqueduct doesn’t use cement and mortar. Instead, each stone is perfectly placed among the others, held together by nothing more than gravity.

The secret that makes this aqueduct possible — along with most of Rome’s legendary infrastructure — is the Roman arch. The arch’s simple design distributes pressure outwards, supporting far more weight than a column or beam could. This gave architects the ability to create buildings that bore immense loads, sending Roman construction soaring skyward.

That humble arch is one of the Roman Empire’s greatest gifts to civilization. Many of history’s most inspiring buildings — from the cathedrals of the Medieval and Gothic eras to the mosques of the Middle Ages and Renaissance — could never have been built without them. Wherever they appear, arches carry the weight of Rome’s powerful legacy.

Strength in Simplicity

One of the empire’s best-kept structures is in fact in France: Maison carrée, Nîmes

“Simplicity is the ultimate sophistication” — Leonardo Da Vinci

From her legislative workings to her battle formations, Rome stuck to the same formula. She discovered straightforward strategies that worked, and she mastered them. 

This, in essence, was the secret of Rome's success: perfect the essentials and eliminate everything else

That inspired simplicity gave her buildings the strength to last millennia. After all, what better way to maintain buildings than by creating ones that repair themselves, use gravity to move water hundreds of miles, and implement beautiful and functional structural designs to support their own weight?

These principles of simplicity gave Rome the ability to extend the bounds of civilization farther than anyone could have imagined. The empire’s great libraries, public sanitation, and flourishing education all depended on architecture: aqueducts, roads, and more.

Overcomplexity was Rome’s downfall. When the empire grew so vast that it was impossible to legislate effectively, enemies began to eat away at the edges. The weakening empire was pierced by invasions that demolished and pillaged the empire’s buildings — their natural longevity would have kept many more standing if not for this. 

In today’s era of cutting-edge building techniques that nonetheless struggle to produce anything as beautiful and lasting as Rome did, these architectural wonders prompt us to ask: is overcomplexity undermining our culture?

And could simplicity perhaps be our secret to success?

Art of the Week

School of Athens, Raphael (1511)

As part of a series of frescoes that decorated the pope’s study, Raphael’s School of Athens demonstrates the harmony between pre-Christian philosophy and the Christian faith.

The painting depicts the intellectual greats of history assembled in one courtyard. Plato and Aristotle, the greatest thinkers of Western civilization, take center stage. They’re surrounded by geniuses of other disciplines, like mathematicians Pythagoras and Archimedes, and contemporary artists like Da Vinci and Michelangelo. 

The setting is just as important as the figures. Raphael consulted architects to help him sketch the Greek courtyard that forms the backdrop of his fresco. The courtyard’s floor plan forms a cross, hinting that the philosophers’ search for truth is ultimately framed within Christianity. 

The architecture’s clean lines capture the classical beauty of the Greco-Roman world. Though seeming stark, the lines of the fresco are structured around the Golden Ratio, creating a mysterious harmony that needs little decoration.

It’s this beauty — stark, mathematical, and mesmerizing — which defines Greek and Roman architecture, and which, after thousands of years, still manages to capture our awe and attention.

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