The Great Pyramid was built white: smooth, polished limestone from base to tip, and about eight metres taller than it is today. So where did that skin go?

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This is the Great Pyramid of Giza. Or rather, this is what's left of it. Those rough, stepped blocks were never meant to be seen. When it was finished, about four and a half thousand years ago, the whole thing was wrapped in a skin of fine white limestone, smooth and polished until it shone. It was also about eight metres taller than it is today. So where did that skin go? Who took it? And is any of it still there? To answer that, you have to understand how it was built. And the real evidence is more surprising than any theory. A work diary written by the men who hauled its stone. A ramp found in 2018. And a whole town built just to feed the builders. So how do you build a mountain? It was built for a king named Khufu. Strangely, the only complete statue of him that survives is about seven and a half centimetres tall. You could hide it in your fist. His tomb went the other way. About a hundred and forty six metres high. Each side of the base about two hundred and thirty metres long, and the four sides match to within a few centimetres. It's lined up with true north to within a fraction of a degree. Not perfect, the base is very slightly out of square, but close enough to embarrass plenty of modern builders. Inside are an estimated two million blocks or more. Around six million tonnes of stone. So where do you find six million tonnes of stone? Most of it, it turns out, was cut right there. The builders quarried the core blocks from the Giza plateau itself, just south of the pyramid. They even left a natural knoll of bedrock inside it, saving themselves a few layers of work. But the white skin needed better stone. That came from Tura, across the Nile, about fifteen kilometres away. A fine, even limestone that could be polished. Those quarries were worked for thousands of years. This is one of them, photographed in 1904. And deep inside, the king's burial chamber is built from granite. Beams weighing tens of tonnes each, shipped from Aswan, hundreds of kilometres up the Nile. Cutting the stone was one problem. Moving it was the real one. And in 2013, archaeologists found the paperwork. On Egypt's Red Sea coast, at a place called Wadi al-Jarf, a French-led team found rolls of papyrus stored in an ancient harbour. They are the oldest inscribed papyrus documents ever found. And they turned out to be a logbook. It was kept by an official named Merer, who led a crew of boatmen. Near the end of Khufu's reign, Merer's crew shipped fine white limestone from Tura to a place the diary calls the Horizon of Khufu. That's the pyramid. They made two or three round trips every ten days, and stopped overnight at a basin called the Lake of Khufu, probably dug for the project. And Merer's boss appears in the diary too. Ankhhaf, the king's half-brother. But how did boats reach a pyramid on a desert plateau? Every year the Nile flooded, and as this old photograph shows, the water could come right to the edge of Giza. Scientists studying ancient pollen in sediment cores think a now vanished branch of the Nile once ran close to the plateau, letting boats reach a harbour at its foot. So the stone came by water, almost to the door. The last stretch was dry sand. On land, the blocks rode on wooden sledges, dragged with ropes. A tomb painting from about seven hundred years later shows how. Dozens of men haul a colossal statue on a sledge. And at the front, one man is pouring water onto the sand. For a long time, people read that as ritual. Then in 2014, physicists in Amsterdam tested it. Dry sand piles up in front of a sledge. With the right amount of water, the sand stiffens, and the force needed to pull it can drop by about half. Too little water does nothing. Too much turns it to mud. The man with the jar may have been the most important engineer in the picture. Dragging stone across flat ground is one thing. Lifting it a hundred and forty six metres is another. Egyptians certainly used ramps. Remains of construction ramps survive at other pyramid sites. But for the Great Pyramid, nobody knows exactly how they were laid out. Maybe one long straight ramp. Maybe ramps zigzagging up one face. Maybe one wrapping around the pyramid like a spiral. One architect even argues for a ramp inside the pyramid. It's a theory. No one has found it. But in 2018, at an ancient alabaster quarry called Hatnub, archaeologists found something real. A steep ramp, flanked by two staircases lined with post holes. Teams could loop ropes around wooden posts and haul blocks up slopes much steeper than anyone expected. It dates to Khufu's reign or earlier. It isn't at Giza, and it doesn't settle how the pyramid went up. But it shows his people had the know-how. Which leaves the biggest question. Who were these people? The old answer was slaves. The evidence says otherwise. Just south of the plateau, archaeologists have spent decades digging up the town where the builders lived. Bakeries, storerooms, and long halls where work crews slept. They ate well. By one estimate, around a dozen cattle and dozens of sheep and goats arrived every day. When they died, many were buried in their own tombs, right beside the pyramids they built. And inside the pyramid, in chambers no one was meant to see again, work gangs painted their team names. One called itself the Friends of Khufu. Those painted names matter. Some run into the joints and behind blocks that no one could reach once the chambers were sealed. They're part of how we know whose pyramid this is. These were organised Egyptian crews, fed and housed, many probably doing a stint of required service for the king. Not the hundred thousand men a Greek writer described two thousand years later. Probably tens of thousands at most. Herodotus, the Greek writer, was even told that an inscription on the pyramid listed what the workers were paid in radishes, onions and garlic. No one has ever found it. They built it to last forever. For about three thousand eight hundred years, nothing humans built stood taller. And then the city next door came for its skin. That skin was something special. Each casing stone was cut at an angle and fitted so tightly that on the surviving stones, the joints are about half a millimetre wide, still filled with mortar. Around the year twelve hundred, a scholar from Baghdad visiting Giza described the pyramids' surfaces covered in ancient writing. Much of the skin was still there. But Cairo was growing, and here was the finest cut limestone in Egypt, waiting across the river. Taking a pyramid apart is harder than it sounds. In the 1190s, a sultan tried to demolish one of Giza's smaller pyramids. After eight months, his workers gave up, having barely dented it. So Cairo's builders went for the easy part. The skin. Over the following centuries, builders pried the casing loose. Some of it went into new buildings. Some was burned to make lime for mortar. A great earthquake in 1303 shook Cairo, and it's often said to have loosened even more. Tradition holds that pyramid stone went into great monuments, like the Mosque of Sultan Hassan. By the time Napoleon's scholars came to draw it in the 1790s, the pyramid looked much as it does now. Stripped of its top and its skin, it's about eight metres shorter than it was built. The capstone was already gone in Roman times. And no, it was never gold. The capstones that survive from this era, including one found beside Khufu's own small satellite pyramid in 1993, are plain limestone. Stripping the skin revealed something else. You may have heard that the Great Pyramid has eight sides, not four. There's something to it. Each face of the core dips very slightly inward down its centre line, by close to a metre on the north side. From the air, in the right light, every face seems to split in two. A photo taken from a plane in 1940 made it famous. But Flinders Petrie spotted the catch. The casing was thicker down the middle, filling the hollow. The finished pyramid had four flat faces. The extra sides only show because the skin is gone. So after all that, is any of the original skin left? Yes. At the foot of the north side lie a handful of giant original casing stones. They survived because they were buried under the rubble of their own destruction. A British expedition uncovered them in 1837, and Petrie measured them decades later. Some weigh around fifteen tonnes. Next door, the pyramid of Khufu's son still wears a patch of its casing near the top. It's the best hint of what the Great Pyramid once looked like. Imagine it whole. White, smooth, catching the sun above the Nile. And it still isn't done surprising us. In 2017, physicists used particles from cosmic rays, which pass through solid stone, to scan it. They found a huge empty space above the Grand Gallery. In 2023 they confirmed a hidden corridor behind the north face. What the big void was for, nobody knows. This is the Great Pyramid of Giza. Or what's left of it. Follow for more.