As expected, experts are raising doubts over the announcement last Saturday that Egypt's most magnificent pyramid, the Great Pyramid at Giza, contains two unknown voids or cavities. The news prompted speculation about the existence of secret chambers in the monument, strengthening the sense of mystery over the 4,500-year-old pharaonic mausoleum.

According to Egypt's Independent, the Antiquities Ministry slammed as "inaccurate and hasty" the report on the cavities, which is the result of a year-long project presented by the group Scan Pyramids.

The project, carried out by a team from Cairo University and the Paris-based non-profit Heritage, Innovation and Preservation, investigated the pyramid using innovative techniques, including thermography and 3-D simulation. The project also employs muography - using cosmic particles called muons, which permanently and naturally rain on Earth and are able to penetrate any material very deeply.

The first conclusive results revealed two "anomalies." 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.

The news spread around the world, and many outlets associated such cavities with secret chambers or hidden burials.

"Our report is scientifically very accurate and no one has talked about secret chambers, but [instead] cavities," Mehdi Tayoubi, founder of the Heritage Innovation Preservation Institute, told Seeker. "The problem with pyramids is that people are always looking for sensationalism."

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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.

The last remaining wonder of the ancient world has long been rumored to have hidden passageways leading to secret chambers.

But is there a Great Pyramid mystery after all?

The attention has been long focused on four narrow shafts discovered in 1872.

Two shafts extend from the upper, or "Kings Chamber" exit into open air. But the lower two, one on the south side and one on the north side in the so-called "Queen's Chamber" disappear within the structures, deepening the pyramid mystery.

The 8-inch-square shafts remained unexplored until 1993, when German engineer Rudolf Gantenbrink sent a robot through the southern shaft. The investigation failed as the robot stopped in front of a mysterious limestone slab adorned with two copper pins.

In 2002, Zahi Hawass, at that time head of the Supreme Council of Antiquities, used another robot to explore the southern shaft. The operation, carried out on live television, raised more questions than answers. A camera pushed through a hole drilled in the copper pinned door, revealing what appeared to be another door.

Hawass then sent the robot through the northern shaft, but another limestone slab stopped the ride.

As with the Gantenbrink door, the stone was adorned with two copper pins.

What's behind those doors? The question tortured Hawass for years.

RELATED: Cosmic Rays Used to Peer Inside Pyramid: Photos

In 2011 he again explored the pyramid using another robot, named Djedi after the magician who Khufu consulted when planning the layout of the pyramid.

Designed by Leeds University, Djedi provided the first complete look behind Gantenbrink's door. Its "micro snake" camera sent back images of 4,500-year-old hieroglyphs believed to be engineering numbers.

The Djedi project was halted following the Egypt revolution - and never resumed.

For the new round of investigations, Egypt put aside the rather frustrating experience with robots and turned to innovative and non destructive technologies which include muons.

Of the two anomalies ScanPyramids found, the "void" at the upper part of the entrance gate potentially has the most intriguing shape.

"It's shaped like a corridor and could go up inside the pyramid," Tayoubi said.

However he stressed that any conclusion is premature as more research must be done to define the size, the exact position and the function of such a void.

"Muography for pyramids is like an X-ray for mummies," Tayoubi said. "You detect a broken bone, but you don't know why, when, how, who broke it. The debate is not if the voids are there or not, but what is their purpose."

He agreed many questions can't be answered without the help of Egyptologists.

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"Each specialist must establish a constructive dialogue. We are working with the best institutions in the world with the utmost scientific rigor," he added.

A scientific committee led by the former minister of antiquities Zahi Hawass, approved Scan Pyramids's request to extend the time of the project for another year.

"They really need this time to show us more data," Hawass told Seeker in a phone interview.

"I really believe the void behind the entrance gate has to do with the construction of the descending corridor," Hawass said. "Therefore, we have to exclude the idea of a secret room."

Egyptian authorities have already gone through embarrassment after supporting the theory that a secret room existed in the tomb of King Tut. Such a room would have contained the tomb of Queen Nefertiti.

After much excitement, more detailed scans earlier this year showed that no secret room existed in the tomb of the boy's pharaoh.

A similar outcome could be expected as the ScanPyramids team ends its research next year. The answer could be as simple as it is disappointing.

Photo: The Great Pyramid's known internal structures. Credit: ScanPyramids mission WATCH VIDEO: We Finally Know How the Pyramids Were Made