Egyptian antiquities officials say they have confirmed the existence of a hidden internal corridor above the main entrance of the Great Pyramid of Giza, the BBC reports.
Video from an endoscope showed the inside of the corridor, which is 9m long and 2.1m wide.
The officials say it could have been created to redistribute the pyramid’s weight around the entrance or another as yet undiscovered chamber.
It was first detected in 2016 using an imaging technique called muography.
A team of scientists from the ScanPyramids Project were able to sense density changes inside the pyramid by analysing how it was penetrated by muons, which are by-products of cosmic rays that are only partially absorbed by stone.