During his long career as an engineer, Craig Smith, ’60, has worked on daunting public works projects, including renovations of the Pentagon and repairs after 9-11. But when he visited the pyramids at Giza, modern-day engineering challenges seemed to shrink in comparison. The largest pyramid, built for the pharaoh Khufu beginning about 2551 B.C., is more than 40 stories tall. Smith set out to understand how the Egyptians pulled it off, and gathered his findings in a book, How the Great Pyramid Was Built (Smithsonian Books, 2004). He visited campus last spring to share his insights with Stanford civil engineering and classics students.
So, how did they lug those stones up there?
The Egyptians had neither wheels nor pulleys. To haul and position the massive limestone blocks, which ranged in weight from 2 1/2 to 15 tons, they employed an elaborate series of ramps and a lot of strong backs. Workers applied wet clay, called talfa, to grease the path for wooden sledges pulled by teams of up to 180 men. Total number of stones: 2.3 million.
Pharaoh to architects: think big.
Khufu’s pyramid occupies 13 acres, roughly the equivalent of six football fields. “It’s level within 2 centimeters,” marvels Smith, who speculates that the vast irrigation network built throughout the country made the Egyptians masters at leveling ground. Measurements were made in cubits, which equaled the distance from the pharaoh’s elbow to the tip of his fingers.
It takes a village. Or two, or three . . .
Smith says the organization of the project is as impressive as the construction. “To begin with, you’re in the desert,” he points out. He compares it logistically to building the Hoover Dam—erected in a remote area of Nevada where temperatures rose above 110 degrees—without the benefit of modern communication, refrigeration, sanitation or electricity. In addition to keeping the legions of workers fed and hydrated, project managers had to build miles of roads, erect housing for some 5,000 permanent staff and carve out a harbor. (Heavy wooden beams used to support the interior chambers were transported to the site by boat.)
Hollywood had it wrong.
Historians, not to mention makers of toga movies, long believed that the pyramids were built on the backs of conquered people forced into labor. Smith says recent archaeological evidence and his own findings dispute that notion. “The people who worked there weren’t slaves. They obviously had pride in their jobs,” he says. A worker’s cemetery excavated near the site in one case revealed three generations of family members, all of whom worked on the pyramid. “This was sacred ground, so the fact that the workers were buried there is more evidence they weren’t slaves.”
But it was no day at the beach.
Smith estimates there were about 35,000 workers—5,000 skilled foremen, stonemasons, carpenters, etc., supplemented by 25,000 to 30,000 laborers. The latter were in some sense conscripted. Every member of the kingdom owed a duty to a nobleman, who in turn served the pharaoh. One way to pay this “debt” was to provide labor. “The men worked hard and died young,” Smith says, and accidents were common. Exhumed mummies of workers have revealed deformed vertebrae, broken bones and other signs of trauma, but also evidence of medical care.
Sorry, can’t move 12-ton blocks today.
Meticulous records kept on papyrus or clay tablets document workers’ absences for reasons ranging from “had a fight with his wife” to “working on my house.”
Can I get a six-pack to go?
The workers were paid in bread and beer, or in some cases, grain to make the bread and beer. “The Egyptians invented beer, so I suppose it makes sense that they would use it as payment,” Smith says. A supervisor got four jugs per day. A regular grunt got one. Smith estimates that the workforce at Khufu’s pyramid earned more than 3.3 million jugs of suds each year. To keep up with demand, a brewery operated on site.
