Archaeologists Finally Explained How Ancient Egyptians Cut Granite transcript

In the summer of 1880, a young Englishman arrived at Giza and did something that no one had ever done properly before. He measured everything. His name was William Matthew Flinders Petrie. He was 26 years old. He had no university degree. And he had come to Egypt with a set of precision instruments to find out once and for all how the pyramids were built. He lived in an empty tomb on the plateau. He worked at night to avoid the tourists.

He surveyed the Great Pyramid with a level of accuracy that still impresses engineers today. And while he was doing it, he started picking things up. Fragments of stone, offcuts, broken pieces left behind by ancient workers. And among them were objects that would bother him for the rest of his career. Cylinders of granite, perfectly round, smooth-sided. The cores left behind when ancient Egyptian craftsmen drilled holes straight down into solid granite.

And when Petrie looked closely at one of them, he saw something that didn't make sense. Running around the outside of the core was a groove, a fine line spiraling around the stone like the thread of a screw. Petrie did the maths, and the numbers he came up with suggested that whatever made that groove had bitten into the granite with a force that seemed impossible for people using copper tools. That granite core is still in a museum in London.

People have been arguing about it for more than 140 years. And that argument is where this story begins. Because the question it raises is one of the most famous in all of archaeology. How did the ancient Egyptians cut granite? I've spent a long time on this question. And I want to be upfront with you about where I ended up. I went in thinking the answer was either a mystery nobody could solve or a simple explanation that everyone had already accepted.

It turned out to be neither. The core of this mystery has been solved. There is real, physical, experimental proof of how it can be done. People have done it with their own hands, using nothing the Egyptians didn't have. But the closer I looked at that proof, the more I realized the real mystery was never the one everyone argues about online. It was something else, something that got lost. And it's hiding in plain sight in the stone itself.

And then let me show you what I mean. Let's start with the problem. Because it's a real problem, and anyone who tells you it's simple isn't being honest. Granite is hard, very hard. And archaeologists measure hardness using something called the Mohs scale, which runs from 1 to 10. Talc is a 1. Diamond is a 10. Granite isn't a single mineral, it's a mixture of several, but its main ingredients are feldspar at around 6 and quartz at 7.

Now, look at the metal the Egyptians had for most of their history. Copper. Copper sits at around 3 on the same scale. Even when it's hammered and hardened, it's nowhere near as hard as quartz. Iron didn't come into common use in Egypt until very late in its history. Steel in any modern sense didn't exist. For the pyramid builders of the Old Kingdom more than 4 and 1/2 thousand years ago, copper was [music] it. So, here's the question that has launched a thousand internet theories.

How do you cut a stone that is harder than your tools? It's like trying to carve a diamond with a butter knife. And yet the evidence of granite working is everywhere in Egypt. The King's Chamber inside the Great Pyramid is lined with enormous granite blocks, some weighing many tens of tons, hauled from quarries at Aswan, around 800 km up the Nile. Inside that chamber sits a granite box, the sarcophagus of Khufu, cut from a single block.

There are granite columns, granite statues, granite doorways, granite shrines, and most spectacularly, granite obelisks. Single towering needles of stone, some of them over 25 m tall and weighing hundreds of tons, carved from one piece and raised upright. And it isn't just rough work. Some of these surfaces are flat and smooth. Some are polished to a shine. Some carry crisp hieroglyphs carved deep into the stone. And some, like those cores that Petrie found, show that the Egyptians were drilling perfectly round holes straight into solid granite.

So, when people look at all of this and then look at a copper chisel, the gap feels impossible to close. That's the gap that has produced theories about lost machines, ultrasonic drills, sound, advanced tools from a vanished civilization. I understand why. When I first looked at that spiral groove, I felt it, too. That little jolt of Wait, how? But, I also wanted to know what actually happens when you try it. So, let's go back to Petrie.

Because the first person to seriously wrestle with this problem was also the first person to get something important wrong. And something important right. Petrie published his work at Giza in 1883 in a book called The Pyramids and Temples of Giza. In it, he described the granite drill cores and the saw marks he'd found. He noticed that the Egyptians had used two main tools on hard stone. The first was a saw, a long, straight blade pulled back and forth, cutting a slot into the stone.

You can see the evidence of this on the sarcophagus in the King's Chamber. Petrie noticed places where the saw appears to have run off course or cut too deep, leaving marks that the workers never fully removed. The second was a tubular drill. Not a solid bit like a modern drill, but a hollow tube. As you spin it against the stone, it cuts a ring-shaped groove, leaving a cylinder of stone in the middle. That cylinder is the core.

When the hole is deep enough, you snap the core out. So far, that's not controversial at all. >> [music] >> The evidence for saws and tube drills is overwhelming. The question is, what did the cutting? Petrie looked at the spiral groove on his core, and he looked at the depth of the cuts, and he came to a dramatic conclusion. He thought the Egyptians must have used drills and saws set with fixed cutting points made of something extremely hard.

Jewels essentially. He imagined copper tools with hard stones, perhaps corundum or even diamond, set into their edges like teeth. And he calculated that the drill must have been pushed into the stone with enormous pressure to produce a groove like that. For a long time that interpretation was influential >> [music] >> and it's easy to see why. If you look at a spiral line running around a granite cylinder, it really does look like something cut it, like a tooth dragging through the stone.

[music] But there was a problem with Petrie's idea. No one has ever found an ancient Egyptian saw or drill with jewels set into it, not one. Tens of thousands of objects have been excavated from ancient Egypt. >> [music] >> Copper tools, chisels, workshops, tomb paintings showing craftsmen at work, and none of them show drills or saws studded with hard gems. Petrie's core didn't stop inspiring big ideas though. In more recent decades some writers have looked at the same spiral groove and argued that it points to something far more advanced than jewel-tipped copper.

Machining. Even ultrasonic drilling where a tool vibrates at very high frequencies to cut hard materials. It's a striking idea and I can see the appeal. You look at a regular line spiraling around a stone and your brain goes straight to a lathe or a machine shop. But there's a problem that's hard to get around. Machines leave more than marks. They leave factories, power sources, workshops, metal parts, waste, written or pictorial traces of their use.

And across thousands of years of ancient Egyptian archaeology, none of that has ever been found. What has been found is copper tools, stone pounders, abrasive sand, drill cores, unfinished objects, and paintings of craftsmen using bows and hand tools. So, rather than start with a machine nobody has ever found, I wanted to start with the tools people actually dug up and see how far they could go. So, if Petrie was wrong about the jewels, what was actually doing the cutting?

That's where the story turns. Because it turns out the most important ingredient in cutting granite isn't the tool at all, it's sand. Here's the key idea. And once you understand it, the whole problem looks different. The copper wasn't cutting the granite, the copper was just carrying something that could. Imagine a copper saw blade with no teeth, just a flat edge. Now, imagine you pour dry quartz sand into the slot where the saw meets the stone and you pull the saw back and forth.

The copper isn't hard enough to scratch the granite, but the sand is. Quartz is a seven on the Mohs scale, as hard as the hardest common mineral in granite. And as the saw moves, it drags those sand grains across the stone, pressing them down, grinding them against the surface. Each grain removes a tiny amount of granite, microscopic, almost nothing. But there are millions of grains and the saw is moving back and forth over and over for hours.

The same thing works for a drill. Take a copper tube, spin it against the stone with sand underneath. The tube carries the sand around in a circle and the sand grinds a ring into the granite. This is called abrasion and it's not an exotic idea. It's how people have worked hard stone for thousands of years all over the world. It's related to how we polish gemstones today and how stone saws in modern workshops still rely on hard particles to do the cutting.

The copper in this system is a kind of delivery device. It holds the sand in place and pushes it against the stone and it wears away, too, slowly as the sand grinds against it. And that wear matters more than you might think. Every hour of sawing or drilling eats away at the copper as well as the stone. In experiments, the copper blades and tubes lose a measurable amount of metal as the work goes on. Which means that large granite projects didn't just consume sand and labor.

They consumed copper. The Egyptians mined copper in the Sinai and the Eastern Deserts and sent expeditions to bring it back. Inscriptions and remains of mining camps survive in those regions to this day. When you picture a granite workshop, you have to picture that supply chain behind it. Mines, smelters, expeditions, metal workers making and remaking tools as they wore out. Cutting granite wasn't just a technique, it was an industry.

That sounds like a neat theory, but a theory isn't proof. So, did anyone actually try it? Yes. And this is where the proof comes in. In the 1980s, a British researcher named Dennis Stocks began one of the longest and most detailed experimental projects in the history of Egyptology. His goal was simple and incredibly ambitious. He wanted to recreate ancient Egyptian stoneworking using [music] only the tools and materials that the Egyptians actually had.

No modern machines, no steel, no power tools. He made copper saws. He made copper tube drills. He made bow drills, the kind you can see in ancient Egyptian [music] tomb paintings where a craftsman uses a bow with a string wrapped around a shaft to spin it back and forth. He used flint tools and he used sand. He spent years doing this. Decades, in fact, carefully cutting, drilling, and measuring. And it worked. Stocks sawed through granite with a copper blade and sand.

He drilled granite with a copper tube and sand and produced cores. He measured how much stone was removed. He measured how much copper was worn away. He recorded how long each operation took. He published his results in detail, most fully in a book called Experiments in Egyptian Archaeology. This is the proof. The claim that copper tools cannot cut granite is simply false. Copper tools alone can't, but copper tools used with sand can.

It has been physically demonstrated many times by people working with reconstructed ancient equipment. That part of the mystery really is solved, and I'll be honest, when I first read that, I thought, "Well, that's it then. Case closed." But then, I read more carefully, and I found two things that changed how I saw the whole question. The first was how slow it was. The second was a study that complicated the proof in a way I didn't see coming.

Let's start with speed. Cutting granite with copper and sand works, but it is agonizingly slow. In one modern experiment, researchers using a bow-driven copper tube with abrasive measured a cutting rate of around 5 cubic centimeters of granite per hour. 5 cubic centimeters. That's about a teaspoon. A teaspoon of granite per hour. Stocks' own experiments showed a similar picture. Progress measured in millimeters. Hours of steady, repetitive work to cut a slot you could barely fit your finger into.

Now, think about the sarcophagus in the King's Chamber. >> [music] >> Think about hollowing out a solid block of granite big enough to hold a body. Think about the saw cuts needed to shape its sides. Think about all the granite in the Great Pyramid. This is where a lot of online arguments go wrong in both directions. On one side, people take the slowest experimental rates, multiply them across every granite surface in Egypt, and conclude that it couldn't possibly have been done.

There weren't enough years. There weren't enough people. On the other side, people wave the problem away. Sand and copper, easy, done. Neither is right. Because those calculations often mix up completely different jobs. And this is the moment where the whole problem started to come apart for me, in a good way. We've been treating cutting granite as if it were one thing. It isn't. When you look at how the Egyptians worked granite, you're actually looking at several completely different processes, each with its own tools.

First, you have to get the stone out of the ground. That's quarrying. Then you have to shape it roughly. Knock off the excess. Then, for some jobs, you need straight, precise cuts. That's sawing. For some jobs, you need holes. That's drilling. Then you need to flatten and smooth the surfaces. That's grinding. And finally, for the finest work, you polish. Each of those stages removes stone in a different way, at a different speed, with different tools.

The slow, teaspoon-an-hour work of sawing and drilling isn't how you move the bulk of the stone. It's how you do the precise parts, the detail work, the finishing. So, how did the Egyptians remove the bulk of the granite? To answer that, we need to go to Aswan. And to the greatest failure in the history of Egyptian stoneworking. About 800 km south of Giza, on the east bank of the Nile, the city of Aswan sits on some of the finest granite in Egypt.

Red and pink and gray, [music] flecked with dark crystals. The ancient Egyptians quarried here for thousands of years. And lying in one of those quarries is an object that, if it had ever been finished, would have been the largest obelisk ever made in Egypt. It's called the unfinished obelisk, and it's around 42 m long. Its weight, if it had been completed, is commonly estimated at over 1,000 tons. It's often associated with the reign of Hatshepsut, one of the most ambitious builders of the New Kingdom, around 3,500 years ago.

And it's still lying there. Three sides of it have been freed from the surrounding granite. The top surface has been dressed. Deep trenches run along its sides, but its underside is still attached to the bedrock. It never left the quarry. If it had been finished, the plan would have been extraordinary. The workers would have had to pound their way underneath it, undercutting the obelisk until it rested on only a few supports of rock.

Then, it would have been freed, levered, and dragged out of the quarry. Then moved to the river. Then loaded onto a barge large enough to carry more than a thousand tons, then floated down the Nile, then unloaded, moved again, and finally raised upright. Every one of those steps was a gamble. Everyone depended on the stone holding together, and this one didn't even make it past the first because at some point during the work the granite cracked.

A fissure ran through the obelisk. A monument meant to stand as a single perfect needle of stone was now flawed, and an obelisk with a crack in it is useless. You can't raise it. It might break under its own weight. So, the workers stopped. They walked away. And they left everything [music] exactly as it was. For an archaeologist, this is extraordinary because when a monument is finished, most of the evidence of how it was made disappears.

The tool marks are ground away. The surfaces are polished. The waste is cleared. But, a failed monument is frozen mid-process. The unfinished obelisk is like walking into a factory where everyone put down their tools at the same moment three and a half thousand years ago. It's essentially an ancient crime scene, and the evidence is still there. In the early 1920s, a British engineer and Egyptologist named Reginald Engelbach cleared and studied the unfinished obelisk in detail.

He published his findings, and his work is still one of the key sources on how the Egyptians quarried granite. And when you look at the trenches around the obelisk, you see something very strange. The walls of the trenches aren't smooth. They're covered in curved hollows, overlapping scoop-shaped depressions one after another running along the rock. Some people see these and say they look machined, like something with a rotating head carved into the stone.

I understand that reaction. The scoops are regular. They're rounded. >> [music] >> They repeat. But, here's what else archaeologists found at Aswan. Balls of stone. Hard, dark, heavy stones called dolerite. Dolerite is a volcanic rock that is tough, dense, and very resistant [music] to breaking. The ancient quarries have produced examples of these dolerite pounders, many of them roughly the size of a large grapefruit or a small melon, weighing several kilograms.

And the explanation for the scoops is this: workers stood or crouched >> [music] >> in the trench. They lifted the dolerite pounders and brought them down on the granite again and again and again. Each blow crushed a little of the granite's surface, breaking up the crystals and turning them to powder. The powder was swept away and the worker struck again. A pounder swung from the same position by the same person over and over, naturally produces a curved hollow.

Move a little further along and you start a new one. Line up many workers side by side, each pounding their own section, and you get exactly what you see at Aswan, a row of scoops. This isn't just a theory, either. In the 1990s, a television team working with archaeologists and stonemasons went to Aswan and tried it. They pounded granite with dolerite balls. It worked. It was exhausting. It was slow and it was noisy.

But the granite came away, not by cutting, but by crushing. That's the answer to how the bulk of the stone was removed, not saws, not drills, pounding. Thousands and thousands of hours of human beings hitting granite with harder stones until the rock [music] gave way. And once you see that, the scoop marks stop looking like the work of a machine. They start looking like the work of hands. There's something else at Aswan that tells us about the scale of this effort.

On one of Hatshepsut's great obelisks at Karnak, which is around 30 m tall, >> [music] >> there's an inscription that says the work on the pair of obelisks took 7 months. 7 months. Now, royal inscriptions weren't always modest and we should be careful about taking them at face value, but even so, it gives you a sense of what was possible with a large, organized, skilled workforce working on one enormous project with total state support.

That's the other thing we forget. >> [music] >> The Egyptians weren't a few craftsmen with a copper tube. They were a state with a bureaucracy that could feed, house, organize, and direct large numbers of workers. For projects like obelisks and pyramids, they could throw enormous resources at the problem. If sawing a teaspoon of granite an hour sounds impossible, imagine a hundred workers doing it at once, or a thousand, for months, for years.

The Egyptians didn't need a fast technology. They needed a reliable one. And they had people. >> [music] >> And the work didn't end when the cutting stopped. Some of the most striking Egyptian granite surfaces are not just [music] flat. They shine. Statues of kings with faces so smooth they almost glow. Sarcophagi with surfaces you can see a faint reflection in. That shine comes from polishing. And polishing, too, is a form of abrasion.

You rub the surface with abrasive, starting coarse and moving to finer and finer grades, often with hard stones used as rubbers, until the tiny scratches are so small that the surface reflects light. It's slow, repetitive, and once again, completely dependent on skill. Press unevenly and you get dips and waves. Skip a grade of abrasive and the deeper scratches never disappear. Carving inscriptions into granite was similar.

Hieroglyphs cut into hard stone were likely worked with hard tools and abrasives, rather than simply chiseled with copper, slowly deepening each line until the signs stood out crisply. Every stage, from the quarry to the final polish, followed the same principle. Harder material, patience, and time. So, where are we? The bulk of the granite was removed by pounding with dolerite. The precise cuts were made with copper saws and sand.

The holes were drilled with copper tubes and sand. The surfaces were ground flat and polished with abrasives. All of this has been demonstrated experimentally. It looks like the case is closed, but it isn't. Not quite. Because remember that spiral groove on Petrie's core? We still haven't explained it. And this is where the proof starts to get complicated. In the early 1980s, before most of Stocks's work was widely known, two American researchers named Theodore Gorelick and John Gwinnell carried out a set of drilling experiments.

They published their findings in Expedition, the magazine of the University of Pennsylvania Museum. Their question was very specific. If the Egyptians were drilling with copper tubes and an abrasive, which abrasive was it? Because there are several possibilities. Ordinary quartz sand, crushed quartz, or harder minerals like emery, which contains corundum, a mineral that is harder than quartz. Each of these abrasives behaves differently, and each of them should leave different marks on the stone.

So, Gorelick and Gwinnell drilled. They tried different abrasives. And then they did something that Petrie couldn't have done in the 1880s. They looked at the drilled surfaces under a microscope, and they compared them to the surfaces of ancient drilled stones. What they found surprised me. When they drilled with loose sand or crushed quartz, the holes and cores didn't have the same concentric lines that you see on some ancient drilled stones.

When they drilled with harder abrasives like emery or corundum, they got striations that looked more like the ancient ones. And yet, they were careful to say that they could not determine which of these abrasives, if any, the ancient Egyptians had actually used. Read that again. We can drill granite with copper and sand. That's proven. But in at least one careful experimental study, sand didn't reproduce the exact marks seen on some ancient drill holes.

So, the proof that it's possible is solid. The proof of exactly how the Egyptians did it is not. That's the gap. And it's a real one. Now, before anyone takes that and runs off in the wrong direction, let me be very clear about what it does and doesn't mean. It doesn't mean the Egyptians had machines. It doesn't mean they had lost technology from a vanished civilization. It doesn't mean archaeologists are hiding something.

What it means is that the exact recipe is still being worked out. And there are good reasons why that's so hard. Think about how many variables are involved in drilling a hole in granite with a copper tube. What kind of abrasive? Sand? Crushed quartz? Something harder? How big are the grains? Coarse? Fine? A mix? Is it dry? Or wet? Do you add water? How much? How heavy is the drill? Is weight added on top? How hard do you press?

How fast does it spin? Is it spun with a bow back and forth or turned in one direction? How often do you add fresh abrasive? How often do you clear out the old? About What happens when a grain of sand gets trapped between the tube and the core and gets dragged around? Does it cut a groove? Change any one of those and you change the marks on the stone. And here's the thing. Dennis Stocks, in his decades of experiments, argued that sand could produce grooves and striations on cores, depending on how the drilling was done and how the sand particles behaved as they were crushed and caught between the tube and the stone.

Other researchers have made similar arguments. So, we have careful experimenters who got different results with different methods. That's not a scandal. That's just science working on a very difficult problem. But, it points to something I think is the real heart of this mystery. We have the tools. >> [music] >> We have the materials. What we don't fully have is the know-how. This is the idea that changed the whole story for me.

When people talk about lost technology in ancient Egypt, they usually mean a machine. Something physical. >> [music] >> Something that could be dug up if only we looked in the right place. But, what if the lost technology wasn't a thing? What if it was knowledge? Think about what it takes to drill a perfect hole in granite with a copper tube and sand. You need to know how much pressure to apply. Too little and nothing happens.

Too much and the tube bends or the abrasive gets crushed too quickly or the stone cracks. >> [music] >> You need to know how much sand to use and when to add more. You need to know how to keep the drill perfectly upright so the hole doesn't wander. You need to know how to read the stone, where the grain runs, [music] where the hidden flaws are, when to stop. You need to know which sand is best, which riverbed, which desert, [music] how to sort the grains.

You need to know how to make the copper tube itself and how to keep it round. None of this is written down. There is no ancient Egyptian manual on granite drilling. What we have are tools, workshop debris, unfinished objects and a few paintings. The rest was carried in people's heads, in their hands, passed from master to apprentice generation after generation over thousands of years. And a modern researcher, however brilliant and however patient, is trying to reconstruct in a few years what ancient craftsmen spent their whole lives perfecting.

Think about the difference between you trying to throw a pot on a potter's wheel for the first time and a master potter who has done it every day for 40 years. Same wheel, same clay, completely different result. Now imagine that master potter's entire tradition has been dead for 2,000 years and all you have left are some broken pots and a picture of someone at a wheel. That's what we're dealing with. There's a beautiful piece of evidence for how central this knowledge was to the Egyptians.

In the hieroglyphic script, there's a sign that shows a drill used for hollowing out stone vessels, a crank-like shaft with weights attached. And that sign was used to write the Egyptian word for craft, for skill, for the work of an artisan. [music] In other words, when the Egyptians wanted to write the idea of craftsmanship, they drew a stone drill. For them, drilling stone wasn't just a job. It was the very symbol of skill, and the Egyptians had been drilling stone for a very long time.

Long before the pyramids in the period before the first pharaohs, craftsmen were already producing stone vessels from incredibly hard materials. Bowls and jars hollowed out from the inside with thin walls and elegant shapes. By the time of the Great Pyramid, [music] this tradition was already many centuries old. So, when we look at a granite core with a spiral groove, we're not looking at the first attempt by a people struggling with a new problem.

We're looking at the work of a tradition that had been refining its methods for generations. And that tradition is gone. Not hidden. Not suppressed. Just gone. Because the world stopped needing it. When iron and then steel tools became common, the old methods of working hard stone [music] with copper and sand gradually lost their purpose. Why spend hours with a copper tube when a harder tool could do the job faster? The knowledge didn't need to be destroyed.

It simply [music] stopped being passed on. And there's one more place where the evidence of that knowledge might still be hiding. In the waste. When you drill or saw granite with copper and sand, you don't just create a hole. You create a mess. A fine powder made up of crushed granite, broken sand grains, and tiny particles of copper worn away from the tool. Some researchers have pointed out that this waste could be a kind of forensic evidence.

If you could find the debris from ancient workshops and analyze it, >> [music] >> you might be able to tell what abrasive was used. You might be able to identify the size of the grains. You might even be able to estimate how much copper was worn away. In other words, the answer to the mystery might not be in the finished monuments at all. It might be in the dust. And that's the thing about this whole subject that I keep coming back to.

The evidence is there. Not in a secret chamber. Not in a hidden archive. In [music] the stone. In the quarries. In In cores. In the scoops. In the dust. It's all just waiting for someone to look closely enough, which brings us back to the drill cores. When you look at an ancient granite core under a microscope, you're looking at something remarkable. Every scratch on its surface was made by a real grain of abrasive pushed by a real tool driven by a real person thousands of years ago.

The lines tell you about the pressure, about the rotation, about the size of the grains, about how the work changed as the drill went deeper. The Egyptians didn't mean to leave us a record, but they did. They left the fingerprints of the tool pressed into the hardest stone they worked, and experimental archaeologists are slowly learning to read those fingerprints, comparing ancient surfaces with modern experiments, narrowing down the possibilities, ruling things in and out.

Not all at once, not with a single dramatic discovery, piece by piece. So, has the mystery of ancient Egyptian granite cutting been solved? Here's my honest answer. The big question has been answered with proof. Could the Egyptians cut and drill granite with the tools they had? Yes. It has been demonstrated over and over by people using copper, sand, stone, and their own muscles. We know how they got the stone out of the ground by pounding it with dolerite as the unfinished obelisk shows.

We know how they sawed it, with copper blades and abrasive. And we know how they drilled it, with copper tubes and abrasive. We know how they finished it, by grinding and polishing. >> [music] >> We know it was slow. We know it took enormous organization. We know it relied on huge numbers of people and a very long tradition of skill. None of that requires lost machines. None of it requires a lost civilization. None of it requires anything the Egyptians didn't have.

That's the proof. But, the fine details are still being argued over. Which abrasive, exactly? What method, exactly? Why do some experimental surfaces match the ancient marks and others don't? Those questions are still open and I don't think that's a failure. I think it's the most human part of the story. Let's go back to Aswan one last time. Picture that obelisk. 42 m of granite lying in its trench. Now, picture the people who made it.

Hundreds of workers crouched in the heat lifting heavy stone balls and bringing them down on the rock over and over, day after day, months of work. The noise, the dust, the ache in their arms and shoulders. Picture the overseers checking the lines, measuring the depth, marking the stone with red ochre. Picture the master craftsman, the ones who knew the stone, the ones who could look at a block of granite and tell you where it would break.

And then, picture the moment someone noticed the crack. The moment they realized it was all for nothing. They didn't hide it, they didn't destroy it, they just stopped and they left. And because they left, we can stand where they stood. That failed obelisk is the closest thing we'll ever have to watching the ancient Egyptians at work and it tells us something that I think matters more than any theory about lost machines.

These monuments weren't made by magic, they weren't made by some advanced technology that's been hidden from us. They were made by people, ordinary [music] people with ordinary tools using an extraordinary amount of skill, patience and effort. And somehow that's more impressive because it means that what they achieved wasn't impossible, it was just incredibly hard and they did it anyway. So, I'll leave you with the questions I still can't answer.

What exactly was in the abrasive that made those spiral grooves? How much of the ancient technique was lost when the last copper and sand craftsman died? How many tricks of the trade, how many small crucial details disappeared without ever being written down? What would a master stoneworker from the age of the pyramids think if he saw us with our microscopes and our experiments struggling to repeat what he did every day.

And what else might still be sitting in the quarries of Aswan and in the dust of ancient workshops waiting for someone to look closely enough? Maybe the lost technology of ancient Egypt was never a machine. Maybe it was knowing exactly how to use ordinary things in an extraordinary way. And maybe that's the kind of knowledge that's easiest to lose. If you've ever worked with stone or tried any kind of ancient technique yourself, tell me in the comments what you think those spiral grooves are.

Because on this one, I genuinely think the people who work with their hands might see something the rest of us miss.