The Sphinx Needed 1,400 Years Of Rain. Giza Has Been Dry Since 5000 BC.
The Sphinx is at least 2,500 years older than the king it is said to portray. A laser scan finds 1,400 years of rain cut into its enclosure walls, and a lake core says rain like that ended in 5000 BC.
A months-long reporting project. Documents cited below are held in The Vault and available to readers.
GIZA, Egypt — The deepest runnel on the south wall of the Sphinx enclosure goes 2.1 metres into the rock, and it is rounded at the bottom in the way that only running water leaves a channel.
Forty-one of them run down that wall. A laser scanner measured every one over three nights in June. A block of the same stone, put under the equivalent of 250 millimetres of rain a year in a flume in Cairo, loses 0.64 millimetres a year. The median runnel is 0.9 metres deep.
That is 1,400 years of rain. Giza has not had 250 millimetres in a year since about 5000 BC.
The Sphinx is older than Khafre by at least 2,500 years. That is the finding.
What was said, and by whom
In 1992 Robert Schoch, a geologist at Boston University, said that the weathering on the walls of the Sphinx enclosure was made by rain, and that Egypt had not had rain like that since long before the Fourth Dynasty, to which the Sphinx is assigned.
He was told that wind and salt do the same thing to soft limestone, and that a geologist should stay out of Egyptology. The first objection is a fair one and this newspaper has printed it twice. The second is not an objection.
What we did
We hired a terrestrial laser scanner and a geomorphologist to run it. The permit took eleven days, because a scanner touches nothing.
Dr. Halvard Nkemdirim-Sæther of Tromsø scanned the south and west walls of the enclosure on three nights in June, to a resolution of two millimetres. The scan is published in full with this story, and anyone with the software can measure the walls themselves.
We then asked what rain does to that stone, and how fast. A block of the soft marl of Member II, the band that carries the runnels, was lent to us from the plateau's stone store, where it has sat since the restoration of the 1980s cut it away. Dr. Yusra Bakhoum-Lindgren of Cairo University ran it under a flume for nine weeks at the equivalent of 250 millimetres of rain a year and weighed what came off.
What the walls say
A runnel cut by water is rounded in section and narrows as it goes down. A hollow made by wind is flat-floored and undercuts the wall from the side. Salt leaves honeycomb.
Of the forty-one channels on the south wall, thirty-eight are rounded and narrow downward. Three are undercut and were cut by wind, in the last four and a half thousand years, after the rain had stopped. The wind ones are shallow.
What the rain did, and when
The flume took 0.64 millimetres a year off the marl. Dr. Vantongeren checked the arithmetic and it is in the file. A 0.9-metre runnel at that rate is 1,400 years of rain at 250 millimetres, or longer at less.
Dr. Beatrix Oyinlola-Haugen of Bern reads the Faiyum lake cores, ninety kilometres south-west of the plateau, in which the lake rises and falls with the rain. Her reconstruction puts rainfall at Giza above 250 millimetres a year from about 7400 BC until about 5000 BC, then under a hundred by 4000 BC, then forty-five, then thirty at the time of Khafre. It is twenty-five now.
The walls of the enclosure were open to the sky, and to that rain, for fourteen centuries that ended no later than 5000 BC.
The head
The head is too small for the body. It always has been. The scan gives it a weathering depth one-eighth of the body's, which is what a head recut in the Fourth Dynasty from an older, larger head would look like.
It is also what a harder band of stone would look like, and the head is in a harder band. We do not know which, and we have not said we do.
The core in Dokki
In 1994 the Geological Survey of Egypt drilled a six-metre core through the floor of the enclosure. It was never published. We asked for it and were refused. The refusal is printed whole at the foot of this page, and it says more than we expected.
What this desk takes from it
That the argument about whether rain could have done this ran for thirty-four years on photographs, and the instrument that settles it cost less to hire for a week than this newspaper's hotel in Cairo.
That the number is a date, and not a name. The walls do not say who cut them. They say when the sky stopped cutting them, and that is 2,500 years before the king whose face is said to be on it.
The scan is published. The flume log is published. The core is in a drawer, and the man who holds the drawer has now told us what is in the top of it.
The six o'clock edition
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Sources & Method
We hired a laser scanner and a geomorphologist to measure the enclosure walls instead of arguing about photographs of them; ran a block of the same stone under a flume at a known rainfall to get a rate; and asked a palaeoclimatologist who reads the Faiyum cores when the plateau last had that rainfall. Dr. Vantongeren checked the erosion arithmetic independently. Everything measured is published. The one thing we were refused is described by the man who refused it.
Who we spoke to
- Dr. Halvard Nkemdirim-Sæther, Geomorphologist, Tromsø. Scanned the south and west enclosure walls for this newspaper on three nights under permit; scan published in full June 2026 Classified all forty-one channels by their section before he was told what the flume had found.
- Dr. Yusra Bakhoum-Lindgren, Hydrologist, Cairo University. Ran a nine-week flume test on a Member II marl block lent from the plateau stone store; log published June–August 2026 The block was returned. Her rate is a rate for that block at that rainfall, and she has said so in writing.
- Dr. Beatrix Oyinlola-Haugen, Palaeoclimatologist, Bern. Interviewed by video call three times; supplied her Faiyum rainfall reconstruction at millennium resolution July–August 2026 Her error bars at 5000 BC are plus or minus four centuries. The finding survives both ends of them.
- The Supreme Council of Antiquities, Egypt. Permit for non-contact scanning granted 2 June, eleven days after application; written questions on the 1994 core answered 28 August June–August 2026 Confirms the core exists and refers us to the Geological Survey.
- The Geological Survey of Egypt, Dokki, Custodian of the 1994 enclosure core. Written request for the core; refused; the refusal printed whole under Right of Reply August–September 2026
What we could not confirm
- Who cut it. Nothing on the scanned walls carries a tool mark we can date, a quarry mark or a sign. The channels say when the sky stopped. They do not say whose hands started.
- The head. A weathering depth one-eighth of the body's is what a Fourth Dynasty recut would leave, and it is also what a harder band of stone would leave, and the head is in a harder band. We cannot tell these apart from outside the rock.
- The core. Six metres from the enclosure floor, drilled in 1994, never published, in a drawer in Dokki. We have been refused it and have been told, in the refusal, what its top forty centimetres are. We have not seen them.
How Others Covered This
The same events, as reported elsewhere on the same day. We list what each outlet had that we did not, as well as what we had that they did not — including where we come off worse. Why we print this.
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ApertureThe Face That Waited Out The Rain
An essay on patience, the desert and the gaze.
Had that we did not
The runnels, described better than we have described them.
Left out
A number. There is not one in four thousand words.
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The Hollow PostTHEY HAVE KNOWN SINCE 1992 AND THE PERMITS PROVE IT
Reported the scan as proof of a thirty-year suppression.
Had that we did not
The scan, which is real.
Left out
That the permit was granted in eleven days to a newspaper that asked for it, and that the thing being withheld is a core in a drawer whose keeper has just described its top forty centimetres to us in print.
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They Buriedthis newspaperThe Sphinx Needed 1,400 Years Of Rain. Giza Has Been Dry Since 5000 BC.
Stopped arguing about photographs and measured the wall.
Had that we did not
The scan entire, the flume log, and the refusal.
Left out
We had the scan in June and sat on it for ten weeks waiting for a core we were never going to be given. A newspaper that holds the measured thing back for the sealed thing has the order backwards. — V. Ashcombe-Doyle, standards editor
Right of Reply
They Buried contacted Dr. Mahmoud Abdel-Rassoul-Kearney, Geological Survey of Egypt, Dokki sent the full draft, the scan and the flume log on 25 August; given twelve days. Replied on 5 September. Asked that his reply run whole rather than as a quotation. Printed unedited.
You have sent me a scan and I have looked at it, and it is a good scan. I will begin there, because I would like your readers to know that I am not the man in your story who says a geologist should stay out of Egyptology. I am a geologist.
A scanner measures a shape. It does not measure a cause. Thirty-eight of your channels are rounded and narrow downward, and I agree that water does that. Water also does that when it is dew, running down a wall every morning for four thousand years and dissolving the marl a grain at a time. It does it when it is the Nile flood standing in the enclosure, which it did. And it does it along a joint that was there before any rain, because a joint is where the water goes. Your geomorphologist has classified the channels by their section. He has not classified them by whether they sit on a joint, and I would ask him to.
Your flume is one block at one rainfall for nine weeks. I do not doubt the number. I doubt that a block in a laboratory in Cairo and a wall on the plateau are the same thing, and so does your hydrologist, who has said so, and you have printed that she said so, which I acknowledge.
The Faiyum is ninety kilometres away and it is a lake. I would want a second archive before I put a date on the plateau from it.
Now the core. There is a core. It was taken in 1994 from the floor of the enclosure, six metres of it, and it is in a drawer in this building, and I am not going to give it to a newspaper, because a core of the floor tells you about the floor and your story is about the walls, and because I have watched what newspapers do with a core.
What I will tell you, since you will print this whole, is that the top forty centimetres of it is not limestone. It is silt. Laminated silt, with sand at the base. Silt is what standing water leaves when it goes. I have said that in this building for twenty years and nobody has asked me to say it in print until now, and you may make of that what you like. I make of it that the enclosure held water, and that it held it more than once, and that nobody has dated the silt because nobody has asked to.
Published unedited under our right-of-reply guarantee.
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