Engineering the Egyptian Pyramids: Engineering the Great Pyramid of Giza

This blog is Part Two of a series: Engineering the Egyptian Pyramids. Tune in for a look into the impressive engineering behind the Egyptian pyramids and the modern tech we’re using to uncover their mysteries. 

Part One: Who Built the Egyptian Pyramids and Why

Part Three: Planning the Great Pyramid of Giza

Part Four: How Modern Tech Is Revealing More About the Pyramids

Imagine someone tells you to build a structure. They want it 481 feet tall and 755 feet wide. You have a full fleet of skilled workers at your disposal and a mountain of money. Easy, right? The catch: You have no steel, no concrete, no power tools, no computers, no motorized vehicles, and no wheels. Also, you’re building it all in the desert.

Welcome to ancient Egypt! Judging by what you’ve seen on TV, you probably think this land was filled with miraculous structures, but this isn’t exactly right. Pyramid-building only lasted a few centuries, and the pyramids that you usually see on TV, the Pyramids of Giza, are just a sliver of that timeline. It took 80 years of testing and research to get to those three iconic landmarks.

The Great Pyramid of Giza

One of the Giza pyramids has earned an even higher reputation than its counterparts. It’s a miraculous structure that stuns even today’s architects and engineers: the Great Pyramid of Khufu, also known as the Great Pyramid of Giza.

This pyramid took around 30 years and the equivalent of 10 million modern Americans to build. Although well-known, experts consider it an anomaly compared to the 100+ other pyramids in Egypt, in part due to its massive size and remarkable precision. It was originally 481 feet tall, its base was as big as seven Manhattan blocks, and it had over 2 million stones. This massive endeavor took massive planning.

What is the Great Pyramid made of?

If your king told you to build the greatest pyramid of all time, where would you start? The materials would be a good place. You’ll need something strong, and easy to find. You’ll also need to make sure there’s enough of it. Egyptian architects knew this, and that’s why the Great Pyramid’s location is no accident.

The Great Pyramid sits just a few hundred yards from a quarry filled with limestone, perfect for the pyramid’s inner core, and it’s just a few miles west of the Nile River, ideal for transporting heavy stones. 

The outside of the pyramid originally had smooth, white limestone (later stolen for other projects), which builders took from Tura. This gave the pyramid a dazzling shine that Egyptians saw across the desert. For the pharaoh’s inner tomb, builders traveled south to Aswan and harvested granite (better stone meant better protection).

How is the Great Pyramid so precise?

So you’ve got the materials to build your miraculous pyramid, but how will you put those materials together? As precisely as possible, of course. Each side of the Great Pyramid’s base is almost exactly 755 feet: nearly a perfect square. The base sits almost perfectly flat (within an inch), and each corner is aligned almost perfectly north, south, east and west. The ancient Egyptians had no fancy measuring tools or magnetic compass, but they didn’t need them. Creating a perfect base only took simple math and a good view of the sky.

It started with creating a simple 90-degree angle for the pyramid’s corners. The Pythagorean theorem didn’t officially exist yet, but the Egyptians knew the basic concept: A 3, 4, 5 triangle has a 90-degree corner. Once you have a 90-degree angle, you can make not only perfect corners, but also a leveling tool that measures an almost perfectly flat base.

As for the compass points, there are a few theories. Some say that Egyptian builders documented where stars rose and set and then cut the resulting half circle in two. Others, like engineer and archaeologist Glen Dash, believe that builders placed a stick in the sand during the spring or fall equinox (when the sun rises and sets true east and west) and drew a line on the resulting shadow.

Even with impressive knowledge of science and math, the builders had a tight deadline. They didn’t have any modern tech or materials, but just like today, they had shortcuts.

Although the Great Pyramid is nearly perfect, builders took creative freedom when joining some of the less-visible blocks. Deeper and higher in the pyramid, experts think they may have stuffed gaps with mortar and extra limestone.

What tools did the ancient Egyptians use?

You can’t build anything without tools, but good luck finding a hardware store in 2,000 B.C. Once again, the Egyptians had to get creative. They couldn’t buy tools, but they could certainly make them. The catch: Egyptians only had one metal: copper, a soft metal that made cutting through limestone and granite difficult. Luckily, there’s plenty of abrasive sand in the desert. They added a mixture of powdered rock and sand to the tools, which made them stronger and more durable.     

The Great Pyramid’s Infrastructure

Spoiler alert: Slaves didn’t build the Great Pyramid. Pyramid-building was a community effort, and construction took a massive amount of infrastructure and planning. How do you coordinate a 30-year project that included the equivalent of 10 million modern American workers and transportation and materials spanning hundreds of miles, with no modern tech or even wheels? Find out in Part Three: Planning the Great Pyramid of Giza.