A new scanning technology using deep-penetrating cosmic rays has revealed a large, 100-foot-long chamber inside the Great Pyramid at Giza. This chamber, simply called "ScanPyramids Big Void" for the time being, sits high above the Grand Gallery, at roughly the height of the top of the King’s Chamber, and appears to be the same dimensions as the Grand Gallery itself.

The Big Void was found by muon radiography teams working with the ScanPyramids project, an endeavor that began using muon tomography imaging techniques to perform deep scans of the pyramids at Giza, including the Bent Pyramid, in2015. Muon tomography makes use of short-lived muons, subatomic particle similar to electrons that are produced when cosmic rays strike molecules in the atmosphere. These particles can penetrate deeply into rock before being absorbed, making them useful for this X-ray-like form of imaging, as muons can penetrate the dense limestone structure of the pyramid to reach the imaging plates. Muon tomography was previously used to reveal hidden chambers in the Bent Pyramid in May 2016, and a mysterious void near the Great Pyramid’s entrance on its north face later that year.

This new chamber is the first to have been found in the Great Pyramid since the 19th century, and has been verified by not only three different muon radiology teams, but also with other detection techniques. Because of the relative primitiveness of muon radiography — it is an extremely new technology, after all — little is known about the nature of the chamber, aside from its basic dimensions, and that it is indeed there. Details regarding its structure, and any possible contents remain to be discovered. That is, provided there are any to be found, as the pyramids’ chambers are notorious for being devoid of inscriptions and artifacts.

"This is a premier," exclaims Mehdi Tayoubi, president of the Heritage Innovation Preservation Institute and one of the co-founders of the ScanPyramids project. "It could be composed of one or several structures… maybe it could be another Grand Gallery. It could be a chamber, it could be a lot of things."

"It was hidden, I think, since the construction of the pyramid."