Sometime during the third millennium B.C., workers on the Great Pyramid of Cheops set the last stone in place.

Certainly, they must have felt jubilant, for this event represented a milestone of sorts in one of humanity’ s grandest undertakings.

Although much of the ancient Egyptians’ technology is still a mystery, the enormity and quality of the finished product remain a marvel.

Despite the lack of sophisticated machinery, they were able to raise and fit some 2,300,000 stone blocks, weighing 2 to 70 tons apiece,

into a structure the height of a modern 40-story building.

Each facing stone was set against the next with an accuracy of 0.04 inch,

and the base, which covers 13 acres, deviates less than 1 inch from level (Figure 1.1).