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Satellite radar reveals vast structures beneath the Khafre pyramid

Status: Leading Edge Verdict: Open question: unverified; the method's 2022 paper was retracted in Aug 2026

The claim: A new way of processing satellite radar (SAR) data shows shafts, chambers and huge cube-shaped structures hundreds of metres to about 2 km beneath the Khafre pyramid at Giza.

Where the evidence stands: Announced at press conferences in March 2025 by Corrado Malanga, Filippo Biondi and Armando Mei. The Khafre results have not been published in a peer-reviewed journal. The 2022 peer-reviewed paper that applied the same method to the Great Pyramid was retracted on 10 August 2026 for 'serious methodological flaws and statistical errors'. The authors disagree with the retraction. We list it as Leading Edge with the question open until independent tests are done.

Background

The team says it reinterpreted publicly available radar data from commercial satellites, treating tiny vibrations of the ground as a way to see inside it. They describe eight hollow shafts with spiral paths and two large cubes, and National Geographic reported that the team dates the structures to about 38,000 years ago. Radar specialists quoted by National Geographic and AFP say conventional SAR penetrates only metres into dry ground, and that the reconstructions shown publicly go far beyond what the images contain.

What has been measured

Dates, measurements and documented findings, kept separate from interpretation.

Proponents' main arguments and cited evidence

  • The team says the method uses micro-vibrations recorded in SAR data rather than radar penetration, so normal depth limits do not apply, and that repeated scans gave consistent results. [4][3]
  • Biondi told AFP the team stands by its findings and regards them as objective evidence of large artificial structures. [4]

The mainstream position and its evidence

  • Specialists quoted by National Geographic say SAR detects only a couple of metres below the surface in similar conditions, and the method has not been independently verified. [3]
  • Egyptologists quoted by AFP see no evidence of deep underground networks beneath the plateau. [4]

What evidence would help settle it

Publication of the raw data and processing code, a blind test on a site with known buried features, and an independent check with seismic tomography, ground-penetrating radar or boreholes beneath Khafre.

Sites

Giza pyramids

Related claims

Sources

  1. Biondi, F. & Malanga, C. (2022). Synthetic Aperture Radar Doppler Tomography reveals details of undiscovered high-resolution internal structure of the Great Pyramid of Giza. Remote Sensing 14 (RETRACTED 10 Aug 2026). doi:10.3390/rs14205231 proponent
  2. Remote Sensing editors (10 Aug 2026). Retraction notice for Biondi & Malanga 2022: 'serious methodological flaws and statistical errors'; the authors disagree. doi:10.3390/rs18162679 notice
  3. National Geographic (2025). Is there really a secret city under Egypt's Giza pyramids? (reporting on the March 2025 Khafre claims and expert responses). https://www.nationalgeographic.com/history/article/is-there-a-secret-… background
  4. AFP Fact Check (2025). Experts on claims of 'giant structures' underneath the Giza pyramids, with Biondi's reply. https://factcheck.afp.com/doc.afp.com.42LQ7G3 background

More in this section: Egypt: Sphinx & Giza dating.

Sources checked against Crossref and publisher pages on 2026-10-22. This entry presents a debated idea neutrally: the proponents' case first, then the mainstream position, in our own words. "Open question" is not a judgment that the idea is true or false. Labels describe the claim, not the people who hold it. Methodology.