The ancient Greeks kept a list of seven wonders of the ancient world, a sort of bucket-list for the adventurous tourist. Of the seven, only the Great Pyramid is standing still. Rising to a height of 480 feet above the Giza plateau, it remained the tallest structure in the world until the Lincoln Cathedral surpassed it in 1310 AD.  Its massive pyramidal shape and solid stone masonry stand as a silent witness to the supreme value Egyptians placed on stability. 

ARC/Ancient List

Arabic accounts tell how one of Egypt’s wealthiest and most learned Abbasid caliphs, Abdullah al-Mamun (813-833 AD), the son of Harun al-Rashid (whose deeds were immortalized in Arabian Nights), sought to discover the secrets of the Great Pyramid and its treasure!¹I am following Tompkins 1971, 5 ff. Although the entrance to the pyramid is clearly visible today, in those days it was still hidden behind casing stones. Thus Al-Mamun’s men, in search of the pyramid’s entrance, burrowed into the pyramids north face. After cutting a shaft approximately one hundred feet deep, they heard the sound of something falling inside the pyramid. Apparently, their tunnelling had dislodged a stone in one of the pyramid’s passages. Digging towards the sound, they managed to intersect the passage and thereby gained entrance to the pyramid. The way was opened for Al-Mamun’s men to explore the Descending Passage. No doubt they puzzled over the perfectly strait passage, made from giant blocks of limestone, fitted together with such precision that not even a piece of paper fit between them. The passage led to a chamber deep underground which was roughly hewn and appeared not even to have been completed.

The Lower Chamber was clearly a dead end. They found another passage, but it was blocked with giant granite plugs that were impervious to their pickaxes. Certain that treasure lay just beyond, they burrowed once again into the limestone core of the pyramid, around not one, or two, but three giant plugs which blocked the entrance to the Ascending Passage. With growing anticipation, they climbed the passage for approximately one hundred feet to where it opened onto a cavernous hall. This is the Great Gallery. Another passageway branched off of the Ascending Passage which led to the Queen’s Chamber. This chamber was empty. Backtracking to the Great Gallery, Al-Mamun’s men ascended further into the heart of the pyramid until they reached its upper end. They had only to clamber six feet over the Great Step and the way was clear to enter the main chamber of the pyramid—the King’s Chamber. Surely this room would contain a pharaoh’s treasure! In what was quite possibly the greatest letdown in the history of exploration, Al-Mamun’s men found a granite sarcophagus in the chamber, without its lid, and empty! It is rumored that Al-Mamun secretly had a chest of gold placed in the chamber with enough gold to pay his men and allay their despair.

To what degree any of this actually happened is unknown. I can only repeat the account that was given to me!

Precision

The sheer bulk of the Great Pyramid is awesome, but more astonishing still is the degree of precision with which it was constructed.  Sir Flinders Petrie’s careful measurements have shown that the stone masonry of the Descending Passage does not deviate more than 1/50th of an inch from straight over a span of 150 feet; the sides of the pyramid do not deviate more than 2 inches from square; and the foundations were excavated to within 1 inch of level.²Flinders Petrie, The Pyramids and Tombs of Giza, 24  The pyramid itself is aligned to within 5 seconds arc of true north (.0013 deg).  How the pyramid builders were able to achieve such a precise northern alignment is by no means clear. While it is possible to discern true north by observing the arc of the stars through the night sky there is no easy way to translate these observations into the ground plan of a pyramid.

Proportions

The Great Pyramid incorporates some interesting mathematical proportions into its design.  For example, about one third of the way up the pyramid, the builders lifted a massive limestone block into place, known as “the Great Step.” The face of this stone is approximately six inches from the central axis of the pyramid.  Furthermore, if one were to slice the pyramid horizontally at the level of the base of the Great Step, the area of the section is exactly 1/2 of the area of the base of the pyramid. ³Romer 2007, 44

Another interesting mathematical proportion has to do with the angle of each side of the pyramid—51.5 degrees. This is the slope of a triangle, known as Kepler’s Triangle, which incorporates the Golden Ratio (φ=1.618).⁴If you take the square root of the height of the pyramid (480.6 feet) and divide it by one half the length of the base (378 feet) you get .636 which is the same ratio of a right triangle with a base of 1 and a hypotenuse of φ (the Greek letter Phi = 1.618, also known as the Golden Ratio (not to be confused with Pi = 3.1415). See here for a helpful discussion. Scholars generally attribute this to chance since there is no evidence that the Golden Ratio was intentionally employed in the design of any other structure in ancient Egypt, or anywhere else, until the Greeks constructed the Parthenon. (We will come back to the topic of the Golden Ratio in our discussion of the Parthenon.) But then again, there is no structure in Egypt like the Great Pyramid. It is unlikely, in my opinion, that the builders of the pyramid should have employed this exact ratio by accident, given the importance of selecting a proper slope for the success of the pyramid.

Theories

The precision of the Great Pyramid, and the harmony of its proportions, has generated a great deal of speculation over the centuries. Some early researchers argued that the pyramid was built according to the divine proportions of the cosmos or that its layout represents the prophetic blueprint for all of history.  But as the 19th century marched into the 20th, many of the more extravagant claims for the pyramid were shown to be false. When the German Egyptologist, Ludwig Borchardt, published Against Numerical Mysticism at the Great Pyramid of Giza, he effectively brought most of this speculation to an end, at least within academic circles. Pyramidologists, as they were known, became pyramidiots.⁵Romer 2007, 54 But Borchardt went to the opposite extreme by arguing that the Great Pyramid was not constructed according to a single grand plan but was erected helter-skelter, a little at a time, through the process of “accretion.” This was like arguing that the Mona Lisa was painted one brush stroke at a time by different artists over a span of twenty years.  Even so, the effect of Borchardt’s acidic attack on the pyramidologists is felt to this day and may explain the apparent disinterest displayed by many archaeologists in the pyramids. In the final analysis, it must be admitted that there is much we don’t understand about how they were constructed or what they signify.

Interior Passages

The interior passages of the pyramid were built with the same precision as the exterior. Yet the pyramid’s layout seems somewhat disorderly, as though the pyramid builders changed their mind midway through its construction. For example, they spent a great deal of energy constructing a chamber deep underground before apparently abandoning it in favor of two chambers above ground. Known as the King’s and Queen’s chambers, there is no evidence that the Queen’s chamber was actually used as a burial place. The King’s Chamber, on the other hand, contained a heavy granite sarcophagus which must have been placed there before the chamber was closed.

The decision to place burial chambers inside the pyramid instead of beneath it presented the pyramid builders with a major problem: how to create a hollow space inside a mountain of stone without the whole thing collapsing in on itself.  One solution was to stack limestone blocks, slightly offset, so that the walls of the passageway gradually came together to form an acute triangle—a method known as “corbeling.” The immense pressure exerted by thousands of tons of stone was thereby deflected from the ceiling to the walls. This is how the pyramid builders constructed the Great Gallery.

For the King’s Chamber the pyramid builders chose instead to use granite, which has a high tensile strength, to support the tremendous weight of stone above. It must have seemed like a good choice, and who would dare argue with them? In fact, all of the granite blocks have cracked and will probably fail some day.⁶Petrie, The Pyramids and Temples of Giza, 27 The difficulties involved may explain why this would be the first and last time burial chambers were incorporated inside the pyramid. All subsequent pyramids have their burial chambers located underground.

One final challenge confronting the pyramid builders was the method by which they were to seal the entrance to the Ascending Passage. As you may recall, al-Mamun’s men had to tunnel around three giant blocks of granite, each weighing several tons. Not only did these blocks have to be maneuvered into place during the pyramid’s construction, but they could not have been moved into their final position, blocking the passageway, until the pyramid was completed. How this was done without permanently immuring a group of workers inside the pyramid remains a complete mystery.

Materials

It is estimated that 5,000,000 tons of rock were cut from limestone quarries located near the building site.  Another 220,000 tons of fine Tura limestone were brought to the site from nearby quarries using wooden barges and a system of canals. This bright white, alabaster-like stone was precisely cut and polished so as to form a smooth outer “skin” for the pyramid. Conversely, large quantities of equally well cut dark black basalt stones were used to pave the area next to the pyramid. There must have been some significance to the stark contrast presented by the dark paving stones and the brilliant white casing stones.

Most astonishing of all is the approximately 600,000 tons of granite floated on barges 400 miles down the Nile from Aswan to Giza. The shear bulk of the material used to build the pyramid has called forth wonder in every age. By way of comparison, it is estimated that the Greeks quarried 100,000 tons of marble to build the Parthenon—which is not even 1% of the material required to build the pyramids.

It has been estimated that the amount of time required to quarry and transport the the granite blocks for the inner chambers of the pyramid was equal to the time required to quarry all of the other limestone blocks.  But such estimations are really speculative since we still do not know how the Egyptians were able to quarry massive slabs of granite with the tools available at that time (See: Stone Vase).

Technology

The Greek historian, Herodotus (484-425 BC), records some curious details about the pyramid’s construction.  He says that it took “ten years oppression” to build an elevated road which led from a quay on the Nile to the pyramid.  This road or “causeway” was used to convey stones to the building site. Although nothing remains of the causeway today, enough was visible in Herodotus’ day to elicit wonder and amazement. Herodotus thought the causeway was just as impressive as the pyramid itself!  If the causeway took ten years to construct, the pyramid took another twenty. The historian says that it was built in three stages with stones being lifted from one stage to another using machines “formed of short wooden planks.” (Book II, 125)  Herodotus did not include any pictures. Nor does he elaborate further.  Counter-intuitively, Herodotus says that the uppermost stages of the pyramid were completed first, and then the lower ones.  He concludes his discussion by exclaiming,

Herodotus’ account is generally discounted today. Many scholars argue that Egypt did not even use the wheel at this time. Books offer diagrams with various configurations of ramps which could have been used to haul the stones into place accompanied with statistics showing how an army of masons armed with copper chisels and saws were able to cut and shape the blocks of stone required to build the pyramid in a reasonable amount of time. Thus John Romer theorizes that the first 44 feet of the pyramid (1/4 of the pyramid’s bulk) could have been laid in just a single year by a workforce of 21,000 people.⁷Romer 2007, 74  If we assume a ten hour work day and no weekends, the Egyptians would have had to lay 2.6 stones, weighing 2 1/2 tons on average, every minute!⁸219,000 minutes / 575,000 stones (1/4 of the pyramid’s bulk).

Such theories tend to gloss over some significant unresolved problems.  Firstly, the means by which the Egyptians cut and shaped large blocks of granite, and several million blocks of limestone, is unknown. To borrow a phrase from Mike Tyson, “Everyone has a plan until they actually take a swing at a block of stone with a copper chisel.” And granite? Forget it.

Secondly, it is difficult to conceive of how a single ramp, or even multiple ramps could have allowed the builders of the pyramid to complete it within the lifetime of Khufu: 23 years 365 days a year 10 hours a day 5 million tons of rock = 1 1/3 tons a minute.  For a ramp to be effective, it cannot be too steep; it must to be wide enough to accommodate multiple work gangs coming and going, and durable enough to withstand the weight of an 80 ton granite block. A ramp built to these specifications, 500 feet high, would dwarf the pyramid itself.

The general consensus is that the Egyptians built ramps that spiraled around the sides of the pyramid like llama tracks in the Peruvian Andes. The idea of maneuvering even some of the smaller smaller stones around such a ramp seems quite implausible to me, nevermind the technical challenge of incorporating a spiral ramp into a pyramid shape.

Perhaps the Egyptians really did invent some ingenious machine to move rock, as Herodotus suggests. Certainly, the Great Pyramid displays an astonishing level of technical and organizational skill. And it comes at the dawn of civilization, never to be equaled again.