How was the Great Pyramid of Giza built?

A mountain made by people

About 4,500 years ago, the Egyptian king Khufu began building a tomb for himself at Giza, near where the city of Cairo is today. When it was finished, his pyramid stood about 147 metres high. It is the biggest pyramid ever built, and the only one of the Seven Wonders of the Ancient World still standing.

It is a little shorter today, because the smooth white casing stones that once covered it are gone. Underneath are more than two million stone blocks. On average, each one weighs more than two tonnes, about as much as two small cars.

How did people with no engines, no cranes and no iron tools manage it? For a long time, people could only guess. Now archaeologists have real evidence: the town where the builders lived, the builders' own tombs, and a diary written by a man who worked on the project.

Who were the builders?

An old idea says the pyramids were built by crowds of slaves. Archaeologists now say that is a myth. In 1990, tombs of pyramid workers were found close to the pyramids, and more have been found since. The workers were buried with jars that once held bread and beer for the afterlife. Egypt's archaeology chief at the time said they would never have been buried so honourably if they had been slaves.

Nearby, archaeologists have uncovered a whole town built for the project, sometimes called the Lost City of the Pyramids. It had long barracks along paved streets, bakeries, and craftworkers who made tools and clothes for the workforce. Rubbish left behind shows the workers ate well, with plenty of bread, beer and beef. Some skeletons have broken bones that were set properly, so injured workers were cared for.

Experts think the team included skilled workers employed all year, such as stonecutters, plus labourers from villages across Egypt who took turns working in shifts of a few months. The town could hold up to about 20,000 people, and perhaps around 10,000 were building at any one time.

Merer's diary

In 2013, a French team led by archaeologist Pierre Tallet made an amazing find at Wadi al-Jarf, an ancient harbour near the Red Sea. Stored there were rolls of papyrus, an early kind of paper made from a reed-like plant. They are the oldest known papyri in the world, written more than 4,500 years ago.

Among them was the logbook of an official named Merer, who led a crew of boatmen. He wrote down what his team did, in half-day chunks. Again and again, they loaded their boat with fine white limestone at the quarries of Tura, then sailed along the Nile and its canals to Giza to deliver it.

That Tura limestone was used for the pyramid's smooth outer casing. Merer's diary comes from the last known year of Khufu's reign, so it seems to show the builders adding the finishing touches. It even mentions reporting to Ankhhaf, Khufu's half-brother, who helped oversee the work.

Copper, sledges and wet sand

Much of the pyramid's stone came from a quarry less than a kilometre away. Harder granite came by boat from Aswan, far to the south. Workers cut and shaped stone with tools made of copper, the hardest metal they had. Copper was mined in the Sinai, across the Red Sea, which is one reason harbours like Wadi al-Jarf mattered so much.

Heavy loads were dragged on sledges. An ancient Egyptian tomb painting shows a worker pouring water onto the sand in front of a sledge carrying a giant statue. In 2014, physicists at the University of Amsterdam tested the idea. Sand with the right amount of water is much firmer, so a sledge slides over it more easily, roughly halving the pulling force needed. Too much water makes it harder again.

To lift blocks higher, the builders are generally believed to have used large ramps, with sledges, ropes and levers. But experts still argue about the shape. Did one long ramp run straight up one side, or did ramps zigzag or spiral around the pyramid? A few even suggest a ramp hidden inside. New scanning technology may one day settle it.

A giant team effort

Building the Great Pyramid needed far more than stone. It needed farms to grow grain, herds of cattle, boats, harbours, quarries, copper mines and thousands of organised people. Some archaeologists say the pyramids helped to build Egypt itself, because the farms, boats and supply routes set up for the builders became important to the whole kingdom.

An ancient Greek writer called Herodotus, who visited Egypt about 2,000 years after the pyramid was built, claimed 100,000 people worked on it. The evidence from the workers' town suggests the real number at any one time was much smaller. Real clues, carefully dug up and checked, keep replacing old guesses.

📚 Words to know

Archaeologist

A scientist who studies the past by digging up and examining things people left behind.

Papyrus

A paper-like material made by ancient Egyptians from the stems of the papyrus plant.

Quarry

A place where stone is cut out of the ground.

Sledge

A flat platform on runners, dragged along the ground to move heavy loads.

Friction

The force that makes it hard to slide one thing over another.

🧪 Try this: test the wet-sand trick

1. Fill a baking tray or shallow box with dry sand, or use a corner of a sandpit.
2. Make a "sledge": a small box or plastic container with something heavy inside, such as a few stones or a full drink bottle. Tie a piece of string to the front, and tie a rubber band to the other end of the string.
3. Pull the sledge slowly across the dry sand by the rubber band while a helper measures how far the rubber band stretches, using a ruler. A longer stretch means you needed a bigger pulling force.
4. Sprinkle water over the sand until it is damp but not soupy, and pat it flat. Pull again and measure. Then add lots more water and try a third time.
5. Which pull was easiest? The physicists found that damp sand works best and very wet sand gets harder again. Did you get the same result?