When the Fourth-Dynasty Pharaoh Khufu decided to build the Great Pyramid on the Giza Plateau as his gateway to eternity, he did not realise that the architecture of his burial place would perplex Egyptologists and scientists for centuries afterwards, placing them before a riddle wrapped in an enigma. 

Today, after 45 centuries the mystery of the Pyramids lives on, and the architecture of the Great Pyramid of Khufu still conceals its secrets. Scholars have long carried out scientific and archaeological research on the structure, but nobody has managed to solve all its mysteries. 

Two weeks ago, an international scientific team from Germany, France, Canada, Japan, and Egypt uncovered a nine-metre chevron ceiling corridor at the northern face of the Pyramid and just above its main entrance using five non-invasive techniques: infrared rays, muography, georadar, ultrasound, and architectural and 3D simulation. 

The corridor, which is not accessible from outside the structure, is nine metres long and two metres wide. After the discovery was made, the scientific ScanPyramids team probed a tiny six mm Japanese endoscope through a crack between the stones to attain images of the space from inside. 

Mustafa Waziri, secretary-general of the Supreme Council of Antiquities (SCA), said the function of the corridor is probably to relieve stress from whatever structures lie below, including the opening and upper part of the descending passage around seven metres underneath.

The gabled blocks forming the ceiling of the newly found corridor distribute the weight down and to either side away from the corridor. The function of the corridor is probably similar to the function of weight-relieving chambers above the horizontal passage and antechambers in the Meidum Pyramid in Fayoum. 

The ceilings of the Meidum relieving chambers are corbelled, rather than gabled,

“It is the most important scientific discovery in modern times inside King Khufu’s Pyramid,” former minister of antiquities Zahi Hawass, who heads the committee supervising the project, told Al-Ahram Weekly.

He described the newly uncovered corridor as the “discovery of the century”.

Hawass believes that there is a possibility that the corridor is protecting something which could be the actual burial chamber of king Khufu. Until now nothing of Khufu’s funerary collection has been uncovered except a tiny statue exhibited at the Egyptian Museum in Tahrir Square.

The discovery is part of the ScanPyramids project launched in 2015 to unravel the secrets of the Great Pyramid four millennia after its construction. The project combines several non-invasive and non-damaging scanning techniques to search for the presence of any hidden internal structures and cavities in ancient monuments that may lead to a better understanding of their structure and their construction processes and techniques.

The first phase of the project started in October 2015 when four masterpieces of the Fourth Dynasty, the Bent, and Red Pyramids of king Senefru at the Dahshour Necropolis, as well as kings Khufu and Khafre Pyramids on the Giza Plateau, were scanned. 

A month later, using infrared thermal scanning, anomalies including empty areas in the Pyramids were revealed. At that time scientists said that they could be due to internal air currents or different building materials. 

They also said that the thermal scanning was made at sunrise as the sun heats the structures from the outside, and then at sunset when the Pyramids are cooling down. The speed of the heating and cooling phases was used to uncover “anomalies”, such as empty areas in the Pyramids that could be internal air currents or different building materials.

In December 2015, the second phase of ScanPyramids began with a Muon radiography survey on king Snefru’s Bent Pyramid at Dahshour. The scanners are being used to search for possible hidden chambers within the Pyramid without compromising its infrastructure.

Muon radiography is non-invasive as Muon particles come naturally from the upper layers of the Earth’s atmosphere and are created from collisions of cosmic rays with the nuclei of atoms in the atmosphere.

Kunihiro Morishima from Nagoya University in Japan told the Weekly at that time that the particles fall to the ground at nearly the speed of light with a constant rate of about 10,000 per m2 per minute. 

As with the x-rays used to visualise human skeletons, these elementary particles, like heavy electrons, can very easily pass through any structure, even large, thick rocks and mountains. Detectors placed at appropriate places (e.g. inside the Pyramid and under a possibly undetected chamber) allow the accumulation of Muons over time in order to discern void areas from denser areas as some of the particles are absorbed or deflected.

Muon radiography is now frequently used for the observation of volcanoes, which also involves research teams from the University of Nagoya. More recently, KEK, the High Energy Accelerator Research Organisation, has developed a detection approach based on electronic scintillators that are resistant to nuclear radiation, unlike chemical emulsions, in order to scan inside the Fukushima nuclear power plant reactors in Japan.

In 2016, the Ministry of Antiquities, now the Ministry of Tourism and Antiquities, assigned an archaeological committee led by Egyptologist Zahi Hawass, US Egyptologist Mark Lehner, Czech Egyptologist Murslav Barta, and the late German Egyptologist Rainer Stadelmann to review the findings of the ScanPyramids project.

In the same year, cavities within the Pyramids were identified.

In 2017, the team announced the discovery of a 30-metre void deep within the Great Pyramid situated above the structures of the Pyramid’s Grand Gallery with has a similar cross-section. This left Egyptologists guessing at the purpose of the chamber, and it is not yet known whether it was built with a function in mind. 

The researchers explained that they made the discovery using cosmic-ray imaging recording the behaviour of Muons.

Archaeologist Kate Spence told the US magazine National Geographic and Egyptologist Mark Lehner told the Weekly in 2017 that research has shown that the ancient Egyptians likely built gaps into the Pyramids to relieve pressure and keep them structurally sound.

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* A version of this article appears in print in the 16 March, 2023 edition of Al-Ahram Weekly