How Were the Pyramids Built?

Three pyramids, three pharaohs

About 4,500 years ago, three kings of Egypt each built a pyramid at Giza to be their tomb: Khufu, his son Khafre, and his grandson Menkaure.

Khufu's is called the Great Pyramid. It is as tall as a 45-storey building, and it stayed the tallest thing humans had ever built for almost 4,000 years.

Not slaves: a paid super-team

Archaeologists found the workers' town right next to the pyramids, full of bakeries, breweries and thousands of cattle bones. The builders were Egyptian workers who were fed bread, beer and beef.

Around 20,000 to 30,000 people worked in teams and took turns. Many were farmers who came when the Nile flooded their fields.

Three kinds of stone, three places

• 🟫Rough limestone for the inside, quarried right on the Giza plateau, a short walk away.
• ⬜Smooth white limestone for the outside, from Tura, across the river.
• 🟥Super-hard granite for the king's chamber, from Aswan, 800 km away!

Chisels, wedges and bashing stones

Workers chipped out blocks with copper chisels. Copper is soft, so they had to sharpen them constantly. Wooden wedges hammered into cracks helped split the stone away from the cliff.

Granite was too hard for copper, so they bashed it with balls of dolerite, a rock even harder than granite.

Stone delivered by boat

In 2013, archaeologists found the oldest papyrus with writing on it ever discovered: the logbook of a team leader named Merer. He wrote about ferrying white limestone from Tura to Giza, over and over.

Back then a branch of the Nile ran right next to the pyramids, so boats could unload almost at the building site.

Sledges and the wet-sand trick

On land, blocks rode on wooden sledges pulled by teams of workers. Dry sand piles up in front of a sledge and makes it stick.

The trick: pour a little water on the sand ahead of the sledge. Wet sand is firmer, and scientists proved in 2014 that it takes about half the pulling force.

An ancient Egyptian painting even shows a man pouring water in front of a giant statue on a sledge.

The big mystery: ramps

To lift the blocks higher and higher, the builders almost certainly used ramps. But what shape were they? Nobody knows for sure. Here are the four main ideas.

Many experts think different ramps were used at different heights: maybe a straight one for the bottom, then something that wrapped around.

The ramp with rope-posts

At an ancient quarry called Hatnub, archaeologists found a ramp from Khufu's time with stairs on both sides and holes for big wooden posts.

Ropes looped around the posts worked a bit like pulleys, so teams could haul blocks up slopes of 20 degrees or more, much steeper than anyone expected.

Stars for north, water for level

The Great Pyramid points almost exactly north, off by less than a tenth of a degree. The Egyptians probably lined it up by watching the stars turn around the sky's north pole, or by tracking the sun's shadow.

The base is flat to within about 2 centimetres across 230 metres. Some think they used water-filled trenches, because water always settles perfectly level.

A gleaming white mountain

The rough, stepped core was covered with polished white limestone from Tura. It was so smooth and bright that the pyramid shone in the sun like a giant mirror. The tip may even have been covered in gold.

Most of the shiny casing was taken away centuries later to build houses in Cairo. That's why the pyramids look stepped today. But the core is still standing after 4,500 years.