The Mystery of the Hidden Doors Inside the Great Pyramid

March 22, 1993
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The Great Pyramid of Khufu has fascinated people for millennia. It is the only one of the seven wonders of the ancient world still standing today, and its monumental size and the precision of its design astound thousands of visitors each day. I feel very privileged to have had the opportunity over the course of my career to come to know the pyramid in great depth, and to have discovered one of its greatest secrets - the hidden doors inside the shafts that lead from the so-called “Queen’s Chamber.”

The story of the discovery of the hidden doors began in 1992, when I made the decision to close the Great Pyramid to visitors in order to begin a project to reduce the humidity inside and to correct the damage that was occurring from the accumulation of salt. Each visitor who enters the pyramid leaves behind about 20 grams of moisture from their breath and sweat. When it evaporates, this moisture leaves behind salt deposits, which erode the stone over time. In 1992, we found that the humidity inside the pyramid was hovering around 85%, and salt deposits covered the walls of the Grand Gallery. We cleaned the salt from the walls of the Grand Galley, but we knew that to save the pyramid from irreversible damage, we also had to find a way to reduce the humidity inside.

I contacted Dr. Rainer Stadelmann of the German Archaeological Institute in Cairo, and he arranged for an engineer named Rudolf Gantenbrink to come to Egypt and assist the Supreme Council of Antiquities in installing a ventilation and humidity control system in the pyramid. The first step was to clear the two shafts, each about 20 cm wide and 14 cm high, that lead from the King’s Chamber to the exterior of the monument. We then installed ventilation equipment in the shafts. This project was very successful, allowing us to greatly reduce and stabilize the humidity inside the pyramid.

The shafts themselves are a great mystery. In addition to the two that extend from the King’s Chamber, there are two in the Queen’s chamber as well - one in the northern wall, and one opposite it in the southern wall. No one knows why these shafts were included in the pyramid’s design. An important part of the work in the shafts in the King’s Chamber was sending a small robot inside with a camera attached, to inspect them along their entire lengths. The robot was named “Upuaut,” a different spelling of the name of the god Wepwawet, the “opener of ways.” We learned so much from this exercise about how the King’s Chamber shafts had been incorporated into the construction of the pyramid that we decided to use a robot to inspect the shafts in the Queen’s Chamber as well. Although we knew that the shafts in the King’s Chamber led to the exterior of the pyramid, no one had ever found the outlets for the shafts in the Queen’s chamber. We thought that we might finally be able to solve this puzzle, and perhaps even shed some light on why they were included in the pyramid’s design.

The shafts in the Queen’s Chamber were first discovered in 1872 by a British engineer named Waynman Dixon. The ancient Egyptians had blocked them with stones, making it appear that the walls of the chamber were completely solid. Dixon, however, decided to probe all the joints in the masonry of the Queen’s Chamber with a wire to see if anything might be hidden behind them. When he discovered a hollow in the southern wall, he chiseled through to reveal the shaft. He realized that there was probably a corresponding shaft in the northern wall, and was indeed able to locate one. In the southern shaft, Dixon and his associate James Grant found a small, bronze hook. The northern shaft yielded a granite ball and a piece of cedar-like wood. These objects became known as the Dixon Relics. Both sets of artifacts lay in the rubble at the bottom of the sloping shafts. A report on the discovery of the relics was published in the journal “Nature” on December 26, 1872, including a drawing of the items. In 1993 a search led to the discovery of the ball and hook in the British Museum, where they remain today. The piece of cedar-like wood was missing until 2001, when it was traced to the Marischal Museum in Aberdeen, Scotland.

In 1992, we used Gantenbrink’s robot to take the first look inside the shafts in the Queen’s Chamber. After the solution of a number of technical difficulties, the robot was able to climb about 60 meters into the southern Queen’s Chamber shaft, where it encountered a barricade - a limestone “door” with two copper handles! No one had expected to see such a thing. After making this remarkable find, we sent the robot into the northern shaft. At 18 meters, the robot encountered a bend of about 45 degrees to the left, and was unable to go any further. Gantenbrink returned to Germany, and we were forced to wait until we could find another team to bring in a robot equipped to navigate this bend.

The National Geographic Society agreed to collaborate with the SCA on developing a new robot to explore the shafts in the Great Pyramid. They brought in a firm from Boston, USA, called iRobot to design the machine. Finally, in 2002, we were able to send this robot into the southern shaft and drill a small hole in the limestone blocking. Everyone was amazed when a small camera inserted into the hole revealed a second stone “door” blocking the passage about 20 centimeters beyond the first one! The second door is unlike the first. It looks as if it is screening or covering something, and there are cracks all over its surface. I was so happy to see it, but I couldn’t understand why we had found another door.  

The world watched this discovery unfold live on Fox TV, in a special broadcast. One of the main goals of the documentary was to show the public the evidence left behind by the people who built the pyramids. I talked about the Tombs of the Pyramid Builders, and showed graffiti which names the work gangs that built the pyramids. I even entered the tunnels below the Step Pyramid of Djoser at Saqqara for the first time - I believe that I was the only living archaeologist at that time to have done this, and that it was the first time in history that a television crew had seen the more than 3 miles of winding tunnels below the Step Pyramid.

The television program aired on September 17. Before the show, I went to Hong Kong and Singapore to publicize it, and my friend and colleague Mark Lehner went to Australia, India, and Spain right after the show to discuss the results of our research. Before the show, no one - not even Mark and I - knew what we would find behind the door. One day before the show, we had found out by ultrasound that the door in the southern shaft of the Great Pyramid was about six centimeters thick, which implied that there was something behind it, but no one knew what it might be. We and my National Geographic colleagues wanted to be honest. We prepared ourselves mentally for whatever find (or lack thereof) that we might make. The show was well received by the public all over the world, and was rated “great” by Fox Television in the United States. Half a billion people in China watched the show. Newspapers all over the world covered it on a level that had never before been seen for a television program.

A few days after the Fox broadcast that revealed the second door in the southern shaft, the robot was also able to explore the northern Queen’s Chamber shaft, navigating the sharp bend to the left. It discovered two further, smaller bends to the right at about 23 and 25 meters. We realized that the reason for all of the turns in the northern shaft was that if it had been made straight, it would have crossed paths with the Grand Gallery. The builders had to add the bends to avoid this. Finally, at a distance of about 65 meters from the Queen’s Chamber, the robot found a door very similar to the first one in the southern shaft! The copper handles in the first doors in both the north and south shafts are similar to those on the canopic box of Tutankhamun in the Egyptian Museum Cairo, which were used to pull the box. The doors themselves are made of fine white limestone from Tura, and it seems as thought the handles might have been used to pull them into place.

No one is sure why the builders of the Great Pyramid incorporated the four shafts into the design of Khufu’s monument. Since the shafts in the King’s Chamber open outside of the pyramid, I believe that Khufu’s soul was meant to travel through them. The southern King’s Chamber shaft was intended for Khufu to use as the sun god Ra. It opens exactly between the two boat pits to the south of the Pyramid. Khufu would take the two boats and use them as solar boats for his journey as the sun god through the daytime and nighttime skies – one for the day trip, one for the evening trip. The northern shaft was made for the soul of Khufu as Horus to travel to the eternal circumpolar stars. As for the Queen’s Chamber shafts, I cannot imagine that they had a religious function, as they do not seem to open to the outside of the pyramid - their outlets, if such exist, have never been found in spite of our careful searching. The presence of the doors inside them raises many questions. One idea is that the doors are a challenge that the king must face before he can travel into the afterlife. It is written in the Pyramid Texts that the king will face bolted doors before beginning his journey - perhaps this reference explains the doors’ copper handles. Yet if this is true, why is Khufu’s pyramid the only one with the doors? Also, why are there no doors in the shafts in the King’s Chamber? Logically, we would expect to find them in the shafts that extend from the room where the king’s body was buried. Could it be possible that these doors are evidence that Khufu’s burial chamber might still be hidden somewhere inside his pyramid? The mystery of the doors is one of the most exciting puzzles in Egyptology today.

Finding out what lies beyond the second door in the southern shaft poses great technical challenges - to do this, we will need a robot that can breach the 20 centimeter space behind the first door, and then drill through the second door without causing unnecessary damage to it. I am happy to announce that 2009-2010 will be the year when we finally move forward with this adventure. We have spent many years searching for a team that could help us to develop the equipment needed to carry out this project, but we have finally selected a group that we feel is perfectly qualified to do so. The team is affiliated with Leeds University in the UK. In July of this year, they will bring a new robot to Egypt for final testing, and we expect to be able to go ahead with our work to answer the question of why the mysterious shafts were incorporated into the design of the pyramid, and what lies behind the secret doors!

Further information:
The Cemetery of the Pyramid Builders
External information:
Rudolf Gantenbrink's Upuaut Project Website