Bronze Age · c. 2500 BC · Giza, Giza Governorate, Egypt
Two hidden voids found behind east face of Menkaure pyramid at Giza
Radar, ultrasound and resistivity scans by the ScanPyramids team located two air-filled cavities behind a polished granite patch, supporting the idea of a second entrance.
Peer-reviewed paper
Giza, Egypt Researchers from Cairo University and the Technical University of Munich (TUM) have detected two air-filled voids behind the eastern face of the Menkaure pyramid. It is the third-largest pyramid at Giza. It was built for a Fourth Dynasty king around 2500 BC.
The result is the first solid evidence for an idea proposed in 2019. That idea is that the pyramid has a second, hidden entrance on its eastern side.
The work was part of the ScanPyramids project. The results are published in the journal NDT & E International. The team used only non-invasive methods, which do not damage the structure.
A polished patch of granite on the east face
The eastern face of the pyramid has puzzled researchers for years. The pyramid stands more than 60 metres tall. On this face, one section of granite blocks is unusually smooth and polished. The section is roughly four metres high and six metres wide.
The only other place on the pyramid with a similar finish is the known entrance on the north side. That parallel led the researcher Stijn van den Hoven to suggest in 2019 that a second entrance might lie at this spot.
Three scanning methods, combined into one image
To test the idea, the team examined the facade with ground-penetrating radar, ultrasound and electrical resistivity tomography (ERT). ERT sends a small current into the material. It maps how easily electricity passes through different areas, so pockets of air show up as zones of high resistance.
To reach the necessary accuracy, the team had to bring the data from all the methods together. The researchers call this process image fusion. The press release from TUM says this step played a key role in confirming that the voids exist and in establishing their size.
Two cavities just over a metre behind the wall
The two voids lie 1.4 metres and 1.13 metres behind the outer wall. One is about 1 metre high and 1.5 metres wide. The other measures about 0.9 by 0.7 metres.
According to the team, this is the first time structural irregularities have been confirmed behind this distinctive section of the pyramid.
Following the significant validation of a hidden corridor in the Pyramid of Cheops in 2023, ScanPyramids has once again succeeded in making an important finding in Giza. The testing methodology we developed allows very precise conclusions to be drawn about the nature of the pyramid's interior without damaging the valuable structure. The hypothesis of another entrance is very plausible, and our results take us a big step closer to confirming it.
Christian Grosse, Professor of Non-destructive Testing, Technical University of Munich
What the scans do not show
The scans give the position and size of the cavities. They do not show what the cavities are. Nor do they show whether the cavities connect to a passage, or whether they were built on purpose.
Grosse calls the second entrance a very plausible hypothesis. In his view, the results bring it closer to confirmation.
The corridor Grosse refers to is a hidden space above the entrance of the Great Pyramid of Khufu (Cheops). The ScanPyramids project confirmed it in 2023. As at Menkaure, that work relied on non-destructive techniques to look inside the monument.
Who did the work
Besides Cairo University and TUM, the main contributors were Portland State University, Dassault Systèmes and the Heritage Innovation Preservation Institute. The paper has 20 authors, among them Zahi Hawass, Mehdi Tayoubi and Hany Helal.
The work at the pyramid was carried out in collaboration with Egypt's Supreme Council of Antiquities and the Ministry of Tourism and Antiquities. Both bodies also supervised it.
Sources
Paper: Khalid Helal, Polina Pugacheva, Hussien Allam, Mohamed Fath-Elbab, Mohamed Sholqamy, Olga Popovych, Simon Schmid, Benedikt Maier, Amr Galal, Alejandro Ramirez, Johannes Rupfle, Khalid Taie, Menna Ali, Clarimma Sessa, Thomas Schumacher, Zahi Hawass, Mehdi Tayoubi, Christian U. Grosse, Hany Helal, Mohamed Elkarmoty. Detection of two anomalies behind the Eastern face of the Menkaure Pyramid using a combination of non-destructive testing techniques. NDT & E International, 2025; 155: 103331. DOI: 10.1016/j.ndteint.2025.103331
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