Exactly how did the Egyptians build the Pyramid of Khufu and its two great successors on the Giza Plateau? That question has been debated at least since the time of Herodotus. Many a person has looked upon what the Egyptians are alleged to have wrought, compared it with the early date which historians assign to it, and concluded that the achievement simply wasn’t achievable at all. Needless to say, it’s generally at this point that tales of space aliens, supernatural powers, and super-advanced predecessor civilizations enter the picture.

In truth, though, nothing the Egyptians achieved on the Giza Plateau was impossible for a civilization at their level of technological development. It was just really, really difficult, demanding that virtually all of the resources available to them that weren’t required for the basic maintenance of their civilization be bent in the direction of Giza.

What follows, then, is one narrative, assembled from the best current evidence, of how the Pyramid of Khufu — and thus by extension the other gradated pyramids of Egypt, on the Giza Plateau and elsewhere — were built. It is necessarily speculative, and is doubtless wrong in some details. But it will, at the very least, paint a picture of how such things could have been managed without recourse to magic or any high technology of the sort the ancient Egyptians definitely did not possess. Further, it will provide one set of reasonable answers to questions about why certain things are as they are inside the Pyramid of Khufu in particular, a structure which has long puzzled historians and archaeologists with its unusual number and arrangement of internal passages and chambers in comparison to any of the other pyramids of ancient Egypt.

Of course, would-be builders of any stripe must have sufficient building materials. Those working under Hemiunu to construct the Pyramid of Khufu required no less 5.5 million tons of limestone to complete the project. Even Giovanni Belzoni during his early excavations on the Giza Plateau in 1818 was able to deduce from the archaeological evidence around him that the vast majority of this limestone must have been quarried right there on the plateau. It wasn’t until the 1990s, however, that archaeologists mounted a concerted effort to excavate and understand the quarry sites themselves. They now believe that the Pyramid of Khufu’s insatiable appetite for stone was fed almost entirely from a single quarry located about 650 feet (200 meters) south of the building site.

The quarry was relatively convenient in terms of distance, but decidedly inconvenient in another sense. Moving the stone from it to the building site was a literal uphill battle; the source of the stone lay 125 vertical feet (38 meters) below its ultimate destination. Undaunted, the workers first built a road leading from the quarry to the building site, the remains of which have been partially uncovered by modern archaeologists. Great blocks of limestone, many of them weighing two tons or more, were chipped laboriously out of the bedrock, then levered onto wooden sledges on rollers. These assemblages were then manhandled up the road by teams of ten to twenty workers, using copious amounts of water to lubricate the rollers; illustrations of just such a process have actually been discovered on the walls of ancient tombs. In 1997, under the auspices of the American television program NOVA, a team of researchers was able to duplicate this feat on a small scale. “Although we failed to match the best efforts of the ancient builders,” noted team leader Mark Lehner, “it was abundantly clear that their expertise was the result not of some mysterious technology or secret sophistication, but generations of practice and experience.”

Once the blocks arrived at the building site, they took their places as part of the pyramid. Neither mortar nor anything else was used to anchor the blocks in place. The builders trusted instead to their sheer weight alone, and to the smaller stones and pebbles which they stuffed into the gaps between them. One could thus say that the Pyramid of Khufu is not so much a building or even a piece of monumental sculpture as just an enormous pile of rocks laid down with a very specific shape in mind.

Only the outermost layer of blocks, which has long since been removed from the Pyramid of Khufu that we know today, was constructed of a material shipped in from elsewhere. It was made of fine white limestone from the royal quarries at Tora, the same material which had been used for the pyramid’s platform. While the interior blocks were piled up without a huge amount of concern for precision, these exterior pieces were carefully measured and placed so that they could be smoothed into a perfect, even gradient when construction reached its final stage.

But many years before that would become a concern — in fact, as soon as the very first course of blocks had been placed upon the pyramid’s pavement — a more immediate challenge entered the picture: subsequent courses must be lifted ever higher from the ground in order to rest on top of those that had already been placed. How could such weighty hunks of stone possibly be lifted to such heights using only Bronze Age tools and technologies? This question has provoked more debate than any other aspect of pyramid building. Herodotus, as you may recall, solved the Egyptians’ problem for them by positing the invention of fanciful crane-like machines which were mounted atop the pyramid-in-progress. To go through every other theory that has been broached since the time of the Father of History — even those that don’t rely on supernatural powers or ahistorical fairy tales — would require many thousands of words. Suffice to say, then, that relatively few of the theories expounded in the past still stand up to extended examination in light of what we now know about the ancient Egyptians.

Most of the non-discredited modern theories involve ramps of some sort, although they can differ markedly from that starting point. The most straightforward if perhaps unimaginative of them posits that the workers built up the existing road from the quarry a little more with each successive course of blocks that was added to the pyramid, using stone and clay to elevate it above the ground so that it always led to the current top of the growing structure. In order to keep the slope tenable for the crews hauling the limestone up the road, the Egyptians would have needed to start elevating it further and further back from the pyramid as the latter grew higher. Eventually, the road may have begun its artificial rise above ground level as soon as it exited the quarry itself.

Many other ramp configurations have been proposed as well, from spirals encircling the pyramid as it grew to zigzags climbing up a single face. The chief objection to all of the various hypotheses is that all of the ramps they describe must have demanded a huge amount of time and labor in themselves; Mark Lehner has gone so far as to say that a ramp may have required “as much or more material than the pyramid itself,” only to be demolished when the pyramid was complete. But on the other hand, we do know that the Egyptians were willing to devote staggering resources to their monumental projects. And more practically, none of the various alternative proposals, which like that of Herodotus tend to involve elaborate contraptions of levers, pulleys, and even in some cases wheeled tracks, have ever been demonstrated all that satisfactorily in terms of mathematics, much less in action.

We know that ramps, by contrast, were perfectly feasible for a people at the Old Kingdom’s level of technological development — incredibly difficult to manage, like so much else involved with building pyramids, but feasible. In addition, some measure of actual archaeological evidence lends weight to the ramp theories: fairly clear remnants of building ramps have been found at the sites of two older, unfinished stepped pyramids from the Third Dynasty, and debris which some archaeologists believe may once have been part of an elevated ramp has even been found on the Giza Plateau itself.

So, we can reasonably if not definitively posit here that the Pyramid of Khufu, like its ancestors and descendants, was built using a single long, elevated ramp that was constantly modified to reach ever higher as construction continued. The sheer pace of limestone extraction, transportation, and construction must have been extraordinary, requiring careful management and coordination. We can picture the ramp as a veritable conveyor belt of limestone, part of a smoothly humming assembly line that ran for years if not decades. Some estimates have it that a new block of the stuff must have left the quarry every two minutes throughout each working day in order to win the race against Khufu’s death. As on any assembly line, a breakdown at any point along its length could be disastrous to the timetable. Workers in the quarry must have been under immense pressure to feed the latest block of freshly cut limestone to the waiting transportation crews; the crews on the ramp must have striven to stay ahead of the sledges coming up behind them; workers on the pyramid itself must have rushed to set the current block into its allotted place before the next one arrived from below. It was undoubtedly stressful and exhausting to a degree we can scarcely begin to imagine, but perhaps it was just a little exhilarating as well, in that way which hard work under pressure can sometimes be. Certainly the graffiti the workers left behind points to individual teams who were proud of their speed and efficiency, who suffered no lack of camaraderie, who delighted in trying to outdo their counterparts.

Once the pyramid passed about 60 feet (18 meters) in height, it was time to begin tunneling into it so that it could fulfill its purpose as the pharaoh’s final resting place. Thus some of the workers began an entrance (1 on the diagram above) on the north face of the pyramid. Even as other workers continued to add to the pyramid’s height above them, these diggers tunneled out a descending passage (4 on the diagram) which eventually reached ground level and continued much further, far below the level of the surrounding structure and the plateau itself. Finally their tunnel reached the horizontal mid-point of the pyramid, and they began to hollow out a large space which Hemiunu probably intended to make into Khufu’s burial chamber (5 on the diagram). Other workers began to hew out other passages leading further south and directly down from this chamber — we don’t know for what purpose — while still others began the work of finishing the roughly cut walls, floor, and ceiling of the descending passage from the entryway to make it into a suitably stately hallway for the acceptance of a pharaoh’s earthly remains.

This original design for the pyramid’s internal spaces has long puzzled Egyptologists in that it bucks a trend in the three pyramids of Khufu’s immediate predecessor Sneferu. Prior to the time of Sneferu, pharaohs were buried below ground level — actually below their pyramids rather than in them, as is the case with Khufu’s first burial chamber here. But Sneferu gradually changed that practice. The floor of the burial chamber inside his first would-be final memorial, the stepped pyramid at Meidum, is at ground level rather than below it; that inside his second, the Bent Pyramid at Dashur, about 3 percent of the way up the structure; that inside his third, the Red Pyramid at Dashur, 8 percent of the way up. Why should Khufu have reverted to a burial chamber deep underground?

Whatever the reasoning, he apparently changed his mind perhaps five years into his pyramid’s construction. Instead of being buried below ground level, Khufu would now be buried high up in the body of the structure — far higher, in fact, than even Sneferu in the Red Pyramid.

Egyptologists have long debated the reasons for this change just as heatedly as they have the question of why the original plan should have been to entomb Khufu underground. While the definitive truth of the matter is impossible to ascertain, a reasonable supposition connects the change in construction plans with the changes in Egyptian religious practice that many believe to have occurred during Khufu’s reign. Was this the point when he decided to declare himself to be the sun god Ra? If so, he must have considered it more befitting of his status to be buried above ground, immortalized there like the sun on its wheeling course above the earth. It’s even possible that Sneferu may have made a similar declaration of Ra-hood at some point during his own reign, only to have Khufu preempt him now. If so, it would be natural for Khufu to desire a burial chamber much higher up in his pyramid than Sneferu enjoyed in the Red Pyramid. As we’ve seen, being a pharaoh was nothing if not a game of one-upsmanship with one’s predecessors.

At any rate, Hemiunu now ordered his workers to abandon their projects underneath the pyramid. Instead he instructed the work crews raising the pyramid from the outside to build into it a hollow rectangular space, thus creating what explorers of later millennia would come to call the Queen’s Chamber (7 on the diagram). The workers also prepared a horizontal passage running away from the Queen’s Chamber (8 on the diagram), and then dug diagonally downward (6 on the diagram) to meet the descending passage extending from the entryway of the pyramid at a point 92 feet (28 meters) down its length (3 on the diagram). Finally, they dug the so-called “well shaft” to meet the descending passage far underground and much further along its length (12 on the diagram), close to the abandoned subterranean chamber.

The precise reasoning behind all of this effort remains unclear today. Our best guess about the well is that it was planned, even at this early date, as an escape route for those who would eventually need to seal the pharaoh’s body within the pyramid; we’ll learn more about how it might have served that purpose shortly. The Queen’s Chamber, however, is even more puzzling. It was certainly not intended for any of Khufu’s queens; Egyptian religious dogma demanded that a pharaoh be buried alone in his pyramid, and in any case Khufu was already providing his favorite queens with their own satellite pyramids. The Queen’s Chamber may actually have been planned as the pharaoh’s burial chamber — its floor is placed at a little over 14 percent of the finished pyramid’s total height, making it substantially higher already than the burial chamber in the Red Pyramid — only to have Khufu once again change his mind and demand to be buried still higher inside his pyramid. Lending credence to this theory is the fact that the chamber, while much better finished than the one underground, does show evidence of not being entirely finished.

In any case, as the pyramid grew yet further, Hemiunu asked the workers to build yet more interior spaces into it. His architects had their work cut out for them to prepare the Grand Gallery (9 on the diagram), the most remarkable single interior space of any Old Kingdom structure. More than 25 feet (7.5 meters) in height and almost 7 feet (2.1 meters) in width, running upward at an incline of 26 degrees for more than 150 feet (45 meters), it’s an awe-inspiring feat of structural engineering by any standard. And yet, unlike so much in ancient Egypt, it wasn’t built simply to inspire awe; it had a very practical purpose. John Greaves in 1637, observing the odd bench-like protrusions attached to each of the walls and the neat holes cut into the benches at regular intervals, concluded that it was all “intended, no question, for some purpose other than ornament.” In this he was correct.

If the architects hadn’t already started thinking seriously about how they would actually seal Khufu inside his pyramid, they clearly began to do so with the Grand Gallery. It was built to accommodate up to 23 massive granite blocks, each just slightly smaller in dimensions than the ascending passage leading up to the gallery. These blocks were slotted into place from above one by one as the Grand Gallery was built — or, perhaps better said, as the rest of the pyramid was built around the Grand Gallery. Each block was kept from sliding down the sloping passage by a wooden beam long enough to span the gallery from one “bench” to the other, with a special protuberance near each of its ends which slotted into the holes in the benches, locking the beam (and thus by extension the granite block) into place. Even once the gallery was finished and sealed with the granite blocks inside, there was more than enough space below the high ceiling for men to walk through it on top of the blocks. As with the well, we’ll see the full purpose of this ingenious design a little later.

When the pyramid had reached a height of about 140 feet (43 meters), it was time to end the Grand Gallery and make the final version of the burial chamber (10 on the diagram). With its floor fully 29 percent of the way up to the pyramid’s planned peak, this elevated location must have satisfied Khufu at last. The King’s Chamber — a space that’s correctly named for once — was built behind a low horizontal passage leading to it from the Grand Gallery, interrupted by three granite portcullises designed to be lowered permanently after the pharaoh’s body was in place (11 on the diagram). This large, immaculately finished chamber measures, as John Greaves was the first to determine, 34.5 feet (10.5 meters) in length, 17 feet (5.2 meters) in width, and 19.5 feet (5.9 meters) in height. The red-granite sarcophagus that would eventually contain the pharaoh’s body was lowered into the chamber before the roof was built over it; it was far too large to be brought in afterward.

With the King’s Chamber complete, all of those interior spaces necessary for the pyramid to carry out its sacred purpose had been prepared. But, concerned about the immense weight of stone that would come to press on their king’s final resting place inside the King’s Chamber, the architects demanded that a series of five more hollow spaces be left above it to relieve the stress. It was here that some of the work crews left behind the only ancient Egyptian writing ever found inside the Pyramid of Khufu, in the form of their poignant, all too human graffiti, their version of “Kilroy was here.” More so than any other aspect of the structure, the graffiti serves as tangible proof that, however otherworldly it may seem, the Pyramid of Khufu was built by people not all that different from you and me.

And then, with these final interior spaces finished, it was “only” necessary to keep stacking stone upon stone, higher and higher, until the man-made mountain was complete.

Granted, you can read many variant versions of the events I’ve just described even without venturing into the dubious realms of alternative Egyptology. Some reject the theory that the subterranean chamber was ever planned as the original burial chamber, or even that the builders’ plans were ever altered midstream at all; some claim that the workers started tunneling out the underground passages before construction even began on the pyramid proper; some claim that only a few granite blocks were placed inside the Grand Gallery, not more than twenty of them; etc., etc. All of these positions come with reasonable arguments and equally reasonable counterarguments, as indeed does the narrative I’ve just advanced.

But there remain also questions that are impossible to answer with any confidence at all on the basis of the available evidence. For example, what was the purpose of the so-called “air shafts” reaching all the way to the pyramid’s surface from the King’s Chamber? Nothing like them is to be found in any other pyramid. Were they intended as a pathway for the pharaoh’s soul to take out of the pyramid and up to heaven? Were they aligned with certain sacred stars in the night sky? Or were they really just intended for ventilation? (If so, they were ineffective.) And what of the similar shafts that begin in the Queen’s Chamber but terminate before they actually reach the exterior surface of the pyramid?

And then there is the recent discovery of a substantial new hollow space inside the Pyramid of Khufu by an international research team who scanned the structure with a new technology which relies on subatomic particles known as muons. Could this space, which is above the Grand Gallery and roughly as large, be yet another abandoned would-be burial chamber? Or could it be something even more exciting? Or, as most respectable archaeologists believe to be most likely by far, is it something more plebeian, a mere artifact of construction like the stress-relieving spaces above the King’s Chamber? For now at least, these questions too remain unanswered. There are no routes in or out of the newly discovered space, which makes accessing it without irrevocably damaging the pyramid around it a problem with no obvious solution.

About the last stage of the pyramid’s construction, however, most people can agree. When they had laid the last course of stone at the pyramid’s peak, ten or fifteen or even twenty years after they had laid the first at its base, the builders began to make their way back down its sides. As they went, they planed and polished the carefully measured and cut outer layer of fine white limestone to form a smoothly gradated surface, whilst filling in the cracks between these outer blocks with mortar.

Tangible evidence of this process can be seen in the depressions that still remain at the four corners of the pyramid’s base to this day, the so-called “keystone sockets” that perplexed and fascinated so many people during the nineteenth century AD especially. These show where the corner casing stones, which actually extended beyond the pavement, once rested — rested, that is, before they were cut and smoothed to form part of the pyramid’s gradated shape. After this trimming was done, the stones inside the sockets filled only half or so of their space — thus doing much to confuse the surveyors of the future, who would wish, by no means unreasonably, to use them as a way of determining the extent of the pyramid’s base when its casing was fully intact.

With the casing complete, the builders needed to add only one more piece to the pyramid, its literal crowning touch. The final pointed capstone, or pyramidion, had been carefully molded out of limestone, granite, or bronze, then coated with pure gold. The day of its installation, marking the official completion of the pyramid, was one of celebration and feasting, presided over by Khufu himself, this god on earth, in his full royal regalia. His pyramid must have been an awesome sight indeed — its sheer white sides glittering in the sun, the gold at its very peak sparkling. Forget the maat and the pharaoh’s eternal spirit and all the rest; the pyramid’s beauty alone must have made all the years of labor seem worth it.

But even after the pyramidion was in place and the feasting was finished, there remained much to be done on the Giza Plateau. Whatever the details of its design, the ramp used to deliver the limestone blocks had to be demolished and hauled away, no small project in itself. And much else had to be built around Khufu’s pyramid in order for it to fulfill its function as maintainer of the maat and home to his earthly cult. This included two temples, two boat pits complete with their contents, and a network of covered, elaborately decorated causeways binding the whole complex together. And then there were the three smaller pyramids of Khufu’s queens, and another still smaller one earmarked as a gathering place for his worshipers after his death.

At last, the day of Khufu’s death arrived. Although opinions among Egyptologists place this event anywhere from 23 to 50 years after he assumed the throne, 30 years strikes many as a reasonable median figure. Regardless of the exact year, we know that all must have already lain in readiness as Khufu breathed his last.

Several months after Khufu’s death, a burial delegation of priests and royalty, led by his son and successor to the throne Djedefre and doubtless including Hemiunu if he was still alive, climbed a ramp to the pyramid’s single entrance bearing the pharaoh’s mummified body, either in a light, minimalist sort of coffin or simply strapped to a board. Given the pyramid’s cramped passages, it wasn’t possible to conduct the body to the King’s Chamber with a great deal of dignity. The priests probably used ropes to slide it down the descending passage to the point where the ascending passage began; then they must have hauled it upward again using the same method. They worked their way up the Grand Gallery, walking on top of the huge granite blocks there, being careful not to jar the beams holding them in place. And so they arrived at the King’s Chamber. Here they placed the body in the sarcophagus where they assumed it would rest for all eternity, saying some final prayers and conducting one last ceremony as they set the lid in place and sealed it with locking pins.

Now it was time to close the pyramid permanently to protect its precious contents. The first or final layers of protection, depending on whether you were on your way out like the priests or in like a would-be robber, were the three granite portcullises in the antechamber just outside the King’s Chamber, each of them weighing three tons, all of them currently propped up by heavy wooden beams. One priest crawled atop the first portcullis to wind a rope through four holes cut into it for that purpose. Other priests trailed this rope into the Grand Gallery and hauled on it, lifting the portcullis just enough for yet another of their number waiting above to knock the beams out from underneath it. They let it drop as gently as possible to the ground, then repeated this same process for the other two portcullises. A loose granite block had been left at the top of the Grand Gallery. The men coated it with plaster to make it slide easier, and pushed it into place to seal the entrance to the antechamber and the King’s Chamber beyond. And with that, stage one of Khufu’s entombment was complete.

Most of the burial delegation now left the pyramid, leaving behind perhaps a dozen or so skilled members of the priesthood for the difficult and dangerous labor that still lay ahead. After smearing the Grand Gallery and the entire length of the ascending passage below it with more plaster lubricant, they stood on top of the lowest of the great granite blocks and, hauling on ropes wrapped around the wooden beam holding the block in place below them, lifted it out of its holes, freeing the block. Sized as it was to fit perfectly into the ascending passage that began at the base of Grand Gallery, the block slowly slid down into said passage as the men atop it made a hasty leap back to the safety of the block behind it, which was still anchored in place by its beam. And so this first block slid all the way down to the very beginning of the ascending passage, helped along through the tight space by the men who pushed it from behind. And so the next block, and the next, and the next, until the entire length of the Grand Gallery was empty and the ascending passage was plugged down almost the entirety of its length with solid granite. It must have been hot, nerve-wracking work in this dark space, requiring equal measures of delicacy, dexterity, endurance, and strength, knowing that a single false move could mean injury or death underneath all those tons of implacable granite. Whether any of the priests actually did die during this Stygian labor is something we can never know.

Now, though, their work was done, and there remained only one way out for the survivors. Like Giovanni Caviglia would do so many millennia later, the priests descended into the well using ropes. But unlike him, they found the shaft unblocked, and so emerged at last near the unfinished subterranean chamber to make the climb back out to the entryway.

Next, a second work crew of priests — for only priests could be entrusted with the secrets of the pyramid’s interior — went inside to put the finishing touches on the job. They pushed more granite blocks that had been left at the junction of the descending and ascending passages deeper into the former, to a point where the passage narrowed and the blocks plugged it up entirely; this sealed off the bottom of the well shaft from any robber who might be brave or foolhardy enough to attempt to climb up it to reach the pharaoh’s burial chamber. The priests then moved a false ceiling into place at the junction point to disguise the plugged ascending passage’s existence.

Finally, back outside, they covered the entryway to the pyramid with a final outer casing block kept on hand for that purpose; this, combined with a judicious application of mortar, disguised the entrance’s existence nicely. Then they removed the ramp that had led up to the entryway.

And with that, their work was done; Khufu was sealed in his pyramid, which stood proudly whole and alone, its perfect form unsullied by ramps or doorways of any sort. The most ambitious building project in human history to date had come to fruition. The Pyramid of Khufu had fulfilled its purpose.

(This series's cover art is by KennyOMG, and is utilized under the Creative Commons Attribution-Share Alike 4.0 International license. A full listing of print and online sources used will follow the final article in this series.)