This amazing fact can only be appreciated from the air.
The Great Pyramid of Giza (whimsically attributed to Pharaoh Khufu) is the only ancient wonder of the world still standing, while the others have succumbed to the passage of time. And despite what the occasional orthodox theory says, it is still unknown how the ancient Egyptians were able to create such a massive structure with the primitive technology of 4,600 years ago. How they transported and cut huge blocks of stone, and then placed them with enviable precision, is still a mystery – and the Egyptians left nothing written about it.
Among some amazing facts, for example, it is worth mentioning that this monument is considered the most precisely aligned structure on the face of the planet, pointing to true north with only a 0.66 degree error.
But did you know that the Great Pyramid also has eight faces? Its apparent four sides are slightly concave, forming a perfect division in its center and doubling that amount.
Curiously, this phenomenon is almost imperceptible from the ground; it can only be fully appreciated from the air and in the appropriate light conditions. In fact, to observe this it is necessary to fly over the pyramid during the sunrise or sunset of the spring or autumn equinoxes, when the sun casts shadows on the monument, as can be seen in the following image:
This amazing feature is mentioned for the first time in Description of Egypt from the late 1700s, written by Sir William Matthew Flinders Petrie, a famous British Egyptologist, who pioneered the use of a systematic method in archaeological study.
Together with his wife Hilda, Sir Petrie excavated several of the most amazing and important archaeological sites in Egypt. On one of those occasions, while studying the Great Pyramid of Giza, the Egyptologist noticed a hollow in the stone core of it, exactly in the center of each face. He was able to measure this “error” and eventually concluded that it was not an engineering failure, but rather an almost invisible attribute of the monument.
The particularity is also mentioned in the book The Egyptian Pyramids: A Comprehensive, Illustrated Reference by JP Lepre. There, on page 65, you can read what is the first sighting of the eight faces from the air:
“A very unusual feature of the Great Pyramid is the concavity in the core that makes it an eight-sided monument, instead of four like the other Egyptian pyramids. That is, its four sides are sunken or indented towards its center lines, from the base to the top. This concavity divides each of the apparent four sides in half, creating a very special eight-sided pyramid; and this is executed with such an extraordinary degree of precision that it falls within the realm of the amazing.
Viewed from any position on the ground or from a distance, this concavity is invisible to the naked eye. It can only be noticed from the air, and only in certain parts of the day. This explains why virtually every available photograph of the Great Pyramid does not show this phenomenon, and why the concavity was not noticed in times before the age of aviation.
‘In fact, it was discovered almost by accident, when in 1940 British Air Force pilot P. Groves flew over the pyramid. So he was able to notice the concavity and capture it in what is now a famous photograph.
What was the purpose?
The exact purpose of the concavities that create an eight-sided Great Pyramid is still a mystery. However, various explanations have been proposed.
For example, at work Concerning the Concave Faces on the Great Pyramid (published in Journal of the American Research Center in Egypt, 20: 1983, pp. 27-32), researcher Martin Isler exposes the following theories:
- To give the core a curved shape and prevent faces from slipping.
- The center block in the original cladding would have been larger and served as a guide for the other blocks on the same course.
- To better bond the core to the cladding.
- For aesthetic reasons, since concave faces would have made the structure more harmonious to look at.
- When the liner stones were removed, they dragged down from the center of the faces, thus creating more wear in the center part.
- Natural erosion produced by the wind, which would have a greater effect on the center.
However, these theories have a big problem. The Great Pyramid is part of a complex, and the other two that accompany it – also devoid of their original coatings – do not have such concavities. To try to explain this, Isler suggests that perhaps, being the first of the three to be built, what was observed is due to an error in the construction technique that was corrected in the later ones.
In the face of so much uncertainty and contradictory theories, then, it is valid to consider – as Petrie affirmed – that the concavities are something totally intentional and had a function that goes far beyond simple engineering.
Other researchers and authors propose that the measurements of these concavities could represent the three durations of the year: solar, sidereal and anomalistic. Although the latter has not been proven.
A striking theory is that of John Williams, author of the book Hydraulic Theory to Cheops’ Pyramid, who argues that the purpose of the concave faces of the Great Pyramid was to contain extremely high internal pressures. Something that points towards the conception of this monument as a power concentrating plant.