Scientists have discovered what appears to be a “big void” located inside of the Great Pyramid in Giza, Egypt.
On Thursday, the journal 'Nature' published the discovery of an open space at least a hundred feet long inside the Great Pyramid.
The Great Pyramid – or Khufu’s Pyramid – was build during the reign of Pharaoh Khufu between 2,509 and 2,483 B.C.
The structure is the largest of the Egypt’s pyramids at Giza, standing about 140 meters (or 460 feet) tall.
“We don’t know whether this big void is horizontal or inclined,” said Mehdi Tayaoubi of the HIP Institute in Paris.
“We don’t know if this void is made by one structure or several successive structures,” he added.
“What we are sure about is that this big void is there, that it is impressive, and that it was not expected as far as I know by any sort of theory.”
It is not known why the space exists or if it holds anything valuable, as it is not obviously accessible.
Scientists detected the cavity using muography, a technique that can sense density changes inside large rock structures.
The Great Pyramid is renowned for its three large interior chambers and a series of passageways, most notably the Grand Gallery.
The newly revealed feature is said to sit directly above this and have similar dimensions to the space below.
Experts think that some of the Great Pyramid’s compartments were included by builders to avoid collapse by relieving some of the pressure from the weight of overlying stones.
A leader of the team behind the discovery said that he believes the void is too large for such a purpose, but noted experts would debate that premise.
“What we are doing is trying to understand the internal structure of the pyramids and how this pyramid has been built,” Cairo University’s Hany Helal told reporters.
“Famous Egyptologists, archaeologists and architects – they have some hypotheses,” he continued.
“And what we are doing is giving them data. It is they who have to tell us whether this is expected or not.”