How Did They Build the Pyramids? — illustrated-library edition cover
VOL 4: ANCIENT MYSTERIES STATUS: UNSOLVED

How Did They Build the Pyramids?

Stone, Sledges, and an Ancient Engineering Mystery

Built ~2560 BC
Status Unsolved
Difficulty Standard
Chapters 9
INVESTIGATE

The Great Pyramid of Giza contains an estimated 2.3 million stone blocks. Its builders used stone and copper tools, ropes, sledges and careful organisation. The scale and surveying skill are remarkable; we can investigate them through the remains they left.

No complete building plan survives, but tools, quarries, settlements and written supply records provide clues. Researchers debate particular lifting sequences. That does not mean every proposed method has a fatal flaw.

It is the oldest of the Seven Wonders of the Ancient World — and the only one still standing.

The Monument

~2560 BC

Built for Pharaoh Khufu of the Fourth Dynasty. Construction took approximately twenty years. It was the tallest structure on Earth for nearly four thousand years.

Stone Blocks

2.3 million

Each averaging 2.5 tonnes. The heaviest granite blocks weigh up to 80 tonnes.

Original Height

146.5 metres

Taller than the Statue of Liberty. Now 138.5 m after losing its limestone casing.

Workforce

20–30k workers

Evidence of organised work crews and provisioning; it does not establish every worker’s legal status.

The Evidence

An artist’s reconstruction of a settlement with houses and work areas.
ARTIST’S VIEW

Evidence of the Work Crews

An imagined workers’ settlement near Giza. Archaeological finds help researchers study food, housing and organisation; the appearance of a drawing cannot settle the workers’ legal status or total number.

Excavations at Giza revealed a workers’ settlement with buildings and food-production areas. Nearby burials and skeletal evidence add information about workers’ lives. Food and healed injuries do not prove that every worker was freely paid.

An illustrated surveyor measuring stonework with instruments.
SURVEY ILLUSTRATION

Skilled Surveying

An imagined survey scene inspired by Petrie’s work. Consult his published measurements for the evidence; the ruler and blocks in this drawing are not a measurement record.

The base was carefully levelled and the sides closely aligned with the compass directions. Surveys estimate the original form from surviving features. Precision shows skilled work; it does not establish an impossible technology.

Two schematic blocks compare particle transmission through more stone and through a route containing an empty space.
HOW MUON IMAGING WORKS

Investigating an Internal Void

The idea behind muon imaging: a route with less stone can allow more particles to reach a detector. These illustrative rays are not measured counts, and the blocks are not a diagram of the Great Pyramid’s chambers.

Muon imaging revealed a large void in 2017. A corridor was examined with a camera in 2023 after earlier detection. Finding a space and explaining its purpose are separate steps.

4,500 Years of Mystery

~2560 BC

The Great Pyramid Built

Pharaoh Khufu's architects oversee the construction of the largest pyramid ever built. 2.3 million blocks, 146.5 metres tall, completed in roughly twenty years.

~450 BC

Herodotus Visits

Herodotus writes about pyramid construction around two thousand years after the event. His account is a later source to compare with archaeology, not a record made by an eyewitness to Khufu’s project.

1880

Petrie's Survey

Petrie surveys the pyramid’s surviving features and investigates its dimensions and orientation. Measurements need methods and uncertainty, rather than isolated numbers presented as perfect precision.

1990

The Workers' Village

Excavations of settlement and burial remains help researchers investigate organised workers, food supply and living conditions. These discoveries do not identify every worker’s status or personal experience.

2007

The Internal Ramp Theory

French architect Jean-Pierre Houdin proposes that a spiral ramp hidden inside the pyramid walls was used to raise the upper blocks. A corner notch supports the theory — but it remains unproven.

2014

Wet Sand Discovery

Experiments show that the right amount of water can reduce friction when a sledge crosses sand. This helps test a hauling method; it does not establish every transport operation at Giza.

2017

The Hidden Void

The ScanPyramids project discovers a 30-metre void above the Grand Gallery using cosmic-ray muon tomography. Its purpose remains completely unknown.

2023

The Secret Corridor

A corridor about nine metres long behind the original entrance is examined with an endoscopic camera after non-invasive detection. Its role is investigated alongside the monument’s other features.

The People in This Story

The Pharaoh

Khufu

The Fourth Dynasty pharaoh associated with the Great Pyramid. Archaeology and written records connect his reign with a large building and supply operation.

The Archaeologist

Mark Lehner

American archaeologist whose work at Giza helped reveal the settlement and supply systems associated with pyramid building. The evidence shows organisation without recovering every worker’s circumstances.

The Architect

Jean-Pierre Houdin

French architect who in 2007 proposed the internal ramp theory — that a spiral ramp hidden inside the pyramid walls was used to raise the upper blocks. His theory predicts a tunnel inside the walls, partially supported by a corner notch.

A restrained watercolour interpretation of the pyramids with small modern visitors.
An artist’s morning view of Giza. The surviving monuments invite investigation; this interpretive landscape is not a photograph or measured site plan.

The Question That Remains

Evidence connects the Great Pyramid with Khufu, Egyptian work crews and large supply networks. Sledge experiments show how damp sand can reduce friction, while a later Egyptian image depicts water used in hauling. Neither establishes every journey made at Giza.

Researchers continue to investigate lifting sequences and the purpose of internal spaces. The open questions sit alongside substantial evidence of Egyptian tools, work crews and organisation.

Read the full book to investigate the key clues and competing explanations — then decide for yourself.

How Did They Build the Pyramids? book cover

Get the Full Book

The complete Pyramids mystery. 9 chapters of evidence, theories, and a question only you can answer.

9 Chapters Ages 8-12 DRM-free EPUB

Part of the Ancient Mysteries Volume

Desert drawings, undeciphered writing, and ingenious ancient machines. Discover what the evidence explains — and which questions remain open.

See all books in this volume →

Keep investigating

Check the evidence

What the evidence supports

Excavations at Giza reveal infrastructure that housed and supplied the pyramid workforce. Ancient Egyptians organised these projects.

Where to be careful

Debate about particular ramps or lifting sequences does not make the builders or their human engineering skills mysterious.

Explore the sources

These selected sources support this guide and offer further reading. Some are written for adults; explore them with a parent or teacher.

The story and illustrations are modern retellings. Imagined scene details are not historical evidence. These sources are a starting point, not citations for every narrative detail.

Evidence guide reviewed 8 September 2026.

Explore HistorIQly