Egypt: Corridor in Great Pyramid of Giza seen for first time
bbc.com
bbc.com
Muon tomography or muography is a technique that uses cosmic ray muons to generate three-dimensional images of volumes using information contained in the Coulomb scattering of the muons. Since muons are much more deeply penetrating than X-rays, muon tomography can be used to image through much thicker material than x-ray based tomography such as CT scanning. The muon flux at the Earth's surface is such that a single muon passes through an area the size of a human hand per second.
https://phys.org/news/2023-02-muon-detectors-remotely-3d-ima...
Unless you book a private visit, you can only go through the Grand Gallery to the King's Chamber.
They keep the Subterranean and Queen's Chambers locked. (For example: they locked me in the Queen's Chamber and forgot about me while I was scanning).
For how long were you locked in the Queen's Chamber?
I particularly like his video [2] on the scoop marks around a partially quarried obelisk, and how the evidence might point to the use of yet to be discovered machinery. Not crazy stuff like alien tech or electrical power tools, but advanced engineering. Perhaps some sort of circular saw or device on a crane.
Edit: After looking into this more elsewhere, the pounding method doesn't seem so ridiculous. Apparently, according to Reginald Engelbach's experiments with the pounding stones by hand, he estimated the excavation of the obelisk would have taken a little over 7 months. That seems reasonable.
Couple that with augmentations of the pounding stone method with wood pikes or even scaffolding and possibly heat, it seems plausible the scoops, which seem to be a misnomer, would be created by those pounding methods and workers working next to each other.
I think the ancient "missing" technology is simply patience.
Would be interesting to hear more about "weakening with alkali" mentioned in the comments.
The alkali bag theory and battle ram in the comments were more plausible though.