Scanning the Great Pyramid: What the Surveys Have Actually Found

The Great Pyramid has been measured, surveyed and speculated about for two centuries, and the honest position for most of that time was that we knew its inside as well as we ever would without taking it apart. Since 2015 that has changed, using a technique that involves neither drilling nor digging.

How You Look Through a Pyramid

Cosmic rays striking the upper atmosphere produce muons, particles that rain down constantly and pass through solid rock. They are absorbed slightly more by stone than by air. Put detectors inside and around a structure, count muons arriving from every direction over months, and denser regions cast a shadow while empty ones let more through.

It is medical imaging logic applied to architecture, with the sky as the source. Nothing is touched, and the pyramid is not disturbed.

What They Found

• The ScanPyramids mission began in 2015, bringing together Egyptian authorities, Cairo University and several international research institutions
• In 2017 the team reported a large void above the Grand Gallery — on the order of thirty metres long, comparable in scale to the gallery itself. It was published in Nature and independently corroborated by more than one detector technology
• In 2023 a corridor of around nine metres was confirmed behind the chevron blocks on the north face, close to the original entrance, and an endoscope was passed through a joint to see inside it

What They Might Be

The leading explanations are structural. Relieving spaces above the King's Chamber already demonstrate that the builders used voids to redistribute load, and the big void may be more of the same on a larger scale. Another line of argument is that it is a construction feature — an internal ramp or a working space left in place. The north-face corridor is most often read as a device to relieve pressure over the entrance, or as connected to how the entrance was originally arranged.

Nothing rules out something more interesting, and nothing supports it either. The pyramid is a tomb whose burial chamber we already have; the base rate for undiscovered treasure inside it is low.

Why It Matters for Visitors

Practically, nothing has changed about what you can walk into — the void and the corridor are not accessible and are unlikely to be. What has changed is the frame. The Great Pyramid is not a solved object in a display case. It is an active research site, with work ongoing, and there is a reasonable chance that something in the guidebook you carry will be out of date within a decade.

Four and a half thousand years of visitors, and it turns out we were standing next to two spaces nobody had noticed. It is a good argument for humility about what else is still in there.