A publication of the Archaeological Institute of America
The author contemplates the notch on the northeast edge of the Great Pyramid at Giza. A chamber beyond the hole in the wall provides new information on the monument's construction. (Gedeon Programme/Dassault Systèmes)
The little thermometer/compass clipped to my bag read 111 degrees as I began climbing the Great Pyramid in search of evidence for how it was built. We know it was the tomb of the pharaoh Khufu and that Hemienu, Khufu's brother, directed its construction some 4,500 years ago. But how the massive limestone blocks were raised has been debated since at least the fifth century B.C., when local priests told the Greek historian Herodotus that cranes were used.
All of the current theories--a long, straight ramp, a ramp that corkscrewed around the outside of the pyramid, or cranelike shadoufs (used in Egypt until recently for irrigating fields)--have serious flaws. In the May/June 2007 issue of ARCHAEOLOGY, architect Jean-Pierre Houdin and I presented a radical new theory: that blocks of stone were raised to the very top of the pyramid on an internal ramp.
We gave what we felt was strong evidence for the theory, which explains a French team's microgravemetric survey in the 1980s that recorded variations in the density of the pyramid. Although the researchers didn't recognize its importance, an image from the survey may show a ramp still open inside the pyramid, running parallel to the outer face of the structure and turning 90 degrees at the corners, corkscrewing up to the top. In the article, we suggested other nondestructive methods of surveying, including infrared and sonar that could yield conclusive proof of an internal ramp. We remain hopeful that we will receive permission to conduct such a survey.
My climb was to investigate another piece of evidence mentioned in the article--a notch about 270 feet up the pyramid's northeast edge. Clearly visible from the ground, the notch measures about 18 feet on each side and is about 20 feet high. Is the notch merely the result of stone robbing, when the finely cut white limestone casing blocks were stripped from the exterior of the pyramid in antiquity? Or was it part of a system to raise blocks via the internal ramp, the remains of a corner left open so blocks could be turned to continue their journey up the next flight of the internal ramp? A closer look was needed, and while filming a National Geographic Channel documentary (Unlocking the Great Pyramid) on the Giza Plateau, we obtained permission to climb up to the notch. The effort was rewarded with discoveries that may help solve this riddle.
I didn't want to be high up on the pyramid in the punishing heat for too long, so the investigation would have to be brief. Jean-Pierre gave me instructions on what to photograph and measure. The French team in the 1980s had reported seeing a desert fox disappear into a crevice near the notch, so along with my camera and tape measure, I took a small flashlight. With me was a cameraman, an experienced Alpine climber, who would record everything in high definition.
We began the ascent in the middle of the north face, climbing above the pyramid's original entrance, because the blocks at the northeast corner are large and the stone there is of poor quality and flakes under foot. About 50 feet up, we worked our way horizontally to the northeast corner. There were only about nine inches of ledge to stand on in some places and the stone was flaking. For a few minutes it was tense, silent climbing, but once we reached the corner, it became rather easy, even in the heat, and a welcome breeze picked up. The blocks here are about three feet high, so it is a bit like climbing a giant staircase. Within 15 minutes we were at the notch.
The internal ramp theory suggests that for the bottom third of the pyramid, the blocks were hauled up a short, straight external ramp. At the same time, a second ramp was built inside the pyramid on which blocks for the top two-thirds would be hauled. This ramp, beginning at the bottom, was put into use after the lower third was completed and the external ramp had served its purpose. Men hauling heavy blocks of stones up a narrow ramp can't easily turn a 90-degree corner, so Houdin suggests that the ramp had openings at each corner where a simple wooden hoist could turn the blocks. The notch two-thirds up the northeast corner could mark such a turning point, and it is precisely at a point where Houdin predicted there should be one.
I had expected the floor of the notch to be flat, but it was quite uneven. Still, it was about 18 feet at its widest--plenty of room for turning blocks. I took photographs of everything Jean-Pierre had requested, then made measurements so he would have the dimensions for later analysis. The big surprise was that at the back of the notch there was a crevice about 18 inches wide and five feet high. As I peered in, I could see what looked like a small room formed of rough blocks. I slipped in and was greeted by the date "1845" painted in black ink on one of the blocks (the rest of the graffiti is illegible). This wasn't virgin territory, but it was still interesting, and I had never seen it mentioned in the pyramid literature. It was a fairly large L-shaped space, with each branch about 11 feet long, 5 feet wide, and 8 feet high. It wasn't the internal ramp, but what was a room like this doing so high up on the pyramid?
By now I had been on the pyramid for about an hour and was starting to feel the heat. I took some quick measurements of the room, photographed what I thought Jean-Pierre would want, and started my descent. As I slowly worked my way down, I began to think about how the room might fit in with Jean-Pierre's theory. The notch, with its irregular measurements and pavement, had been a bit of a disappointment, but the room was something else. Perhaps it was overlooked all these years because the northeast corner is difficult to climb or because it doesn't appear to be significant unless you are thinking specifically in terms of pyramid construction. To me, it seemed unlikely that the room's position just behind the notch was a coincidence, but I just couldn't imagine what its purpose was.
Near the bottom I had to concentrate on my footing as the ledges became narrower and less secure. I could see Jean-Pierre waiting for me below and was eager to tell him of the discovery but had to go very slowly.
Back at the hotel, Jean-Pierre excitedly viewed the pictures. It all made good internal-ramp sense to him--even the roughness of the pavement and the room behind the notch. As he tried to explain all this to my non-architect's brain, he was already planning a computer model of the notch and room that would reveal more about how they may have been used in ancient times.
A few weeks later, Jean-Pierre drew his first sketch of the room and where he believed it was in relation to the internal ramp. The next step was to create a detailed computer model, working as before with engineers from Dassault Systemes, a French corporation that develops 3-D software for designing and testing products. They studied the photos and measurements I had taken and the cameraman's 20 minutes of high-definition footage, and produced their computer simulation, complete with a mini-me in khaki pants and a blue shirt.
The model suggests that the L-shaped room is actually at the intersection of two flights of the internal ramp, where the blocks had to be turned 90 degrees before ascending the next stage. When the pyramid was nearly completed, and almost all the white limestone casing blocks were in place, one of the last tasks for the builders was to fill in the notches that had been left open to provide space for turning the blocks. The L-shaped room was created so that the workers would have the space to bring blocks from the ramp to the notch to complete the filling process.
After a notch was filled, the outlet from the ramp to the L-shaped room was walled up from the inside with blocks and mortar. The top notches would have been filled first, with the builders working their way down the pyramid. This might explain Herodotus's curious statement that "the highest parts of it were finished first, and afterward they proceeded to finish that which came next to them, and lastly they finished the parts of it near the ground and lowest ranges."
The presence of small, open chambers behind each notch would explain why the 1980s microgravemetric survey indicated that the pyramid's four edges were of a lower density than the rest of it. The French team had no explanation, but small rooms behind each notch might be the answer.
Moreover, close examination of the photos and high-definition video revealed several important details about the L-shaped chamber. Some of the stones supporting the ceiling were cut into partial arches, and one block was clearly set in place as a keystone to complete the ceiling. This indicates that the room was planned and built, and is not simply the result of stones being taken away (they couldn't have been removed via the existing 18-inch-wide crevice in any event). Finally, mortar between the blocks that seem to seal off the ramp extrudes into the chamber as would be the case if the blocks were pushed into the chamber from the ramp below. If nothing else, these details strongly suggest the chamber is from the time of the pyramid's construction, and they fit in perfectly with the internal ramp theory.
For now, those who remain skeptical about the theory will need to devise a better explanation for the room's existence, as well as the results of the 1980s microgravemetric survey. If and when the existence of the internal ramp is confirmed by means of one of the nondestructive techniques mentioned above, the best way to enter the ramp would be to remove one or two of the blocks closing the outlet between the ramp and the L-shaped room, permitting the ramp to be investigated directly.
Bob Brier is a senior research fellow at the C.W. Post Campus of Long Island University and a contributing editor at Archaeology. He is coauthor with Jean-Pierre Houdin of Secret of the Great Pyramid. For more on how the Great Pyramid was built, visit archaeology.org/0705/etc/pyramid.html and www.3ds.com/khufu.