The Great Pyramid at Giza, Egypt, has long been rumored to contain hidden passageways leading to secret chambers. Now a team of researchers has confirmed the 4,500-year-old pharaonic mausoleum contains two unknown cavities, possibly hiding a corridor-like structure and more mysterious features.

The announcement by the ScanPyramids project comes at the end of a year-long effort to use various scanning technology on Old Kingdom pyramids, including the Great Pyramid, Khafre or Chephren at Giza, the Bent pyramid and the Red pyramid at Dahshur.

Carried out by a team from Cairo University's Faculty of Engineering and the Paris-based non-profit organization Heritage, Innovation and Preservation (HIP Institute) under the authority of the Egyptian Ministry of Antiquities, the ScanPyramids project used three innovative techniques - muography, thermography and 3-D simulation - to deeply investigate the Great Pyramid of Giza.

An unknown cavity was detected at a height of about 345 feet from the ground on the northeastern edge of the monument, while a "void" was found behind the northern side at the upper part of the entrance gate.

"Such void is shaped like a corridor and could go up inside the pyramid," Mehdi Tayoubi, founder of the Paris-based Heritage Innovation Preservation Institute, told Seeker.

He added that no link can be made between the two cavities at the moment.

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Built for the pharaoh Cheops, also known as Khufu, the Great Pyramid is the largest of a family of three pyramids on the Giza plateau, on the outskirts of Cairo. It's the last remaining wonder of the ancient world.

A striking thermal anomaly was detected in November 2015 by French infrared specialist Jean-Claude Barré on the northern side of the monument, right where four chevrons - blocks placed according to an inverted V-shaped pattern - overhang the descending corridor.

When the pyramid was finished some 4,500 years ago, the chevrons were not visible in that area, but were hidden under casing stones that were dismantled over the centuries.

"Today we still see the remains of those chevrons and oblique stones which most probably are parts of propped missing chevrons covering a kind of void that might have existed before stones were dismantled," the researchers wrote in a statement.

In the construction of the pyramid, chevrons were not used for decoration, but to protect a void and prevent the roof from collapsing.



"Why many chevrons are put to protect such a small area at the beginning of the descending corridor?" the researchers wondered.

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