What’s Inside the Egyptian Pyramids?

In 1789, French General – and later Emperor – Napoleon Bonaparte led a military expedition to capture Egypt from the Ottoman Empire. According to legend, shortly before leading his troops to victory in the Battle of Embabeh, Napoleon decided to spend a night alone inside the Great Pyramid of Giza. The next morning, the General emerged pale and shaken, refusing to discuss what he had experienced. He would remain silent on this for the next 23 years until, lying on his deathbed on the island of St. Helena, he suddenly sat up and began to speak. But a moment later he fell silent once more and, sinking back into his bed, muttered: “Oh, what’s the use? You’d never believe me.”

While this story is almost certainly apocryphal, it perfectly captures the eternal mystery and romance of the Egyptian pyramids. For over 4,000 years, these enigmatic structures have awed and inspired countless travellers, artists, and scholars, standing as silent monuments to a vibrant and advanced civilization that once thrived along the banks of the Nile. But if Napoleon had spent a night inside the Great Pyramid, what would he have seen? What lies beneath the 2.3 million solid stone blocks that make up this grandest of ancient monuments – and what inspired the ancient Egyptians to build these giant structures in the first place? Well, put on your pith helmet and light up your torch as we delve into the history and mysteries of the Egyptian pyramids.

While certainly the most famous, the Pyramids of Giza are not the only pyramids in Egypt – nor even the first or last to be built. Indeed, there are over 180 such structures scattered across the country, their construction spanning a period of over 2,000 years. Pyramid building in Egypt thought to have originated in the 27th Century B.C.E. during the early Old Kingdom period. Prior to this period, kings were buried in low, rectangular mud-brick structures known as mastabas. The above-ground mastaba structure was typically solid, featuring only a small nook or chapel in one wall where offerings to the deceased could be made. The occupant himself was entombed in a burial chamber sunk below the mastaba, along with additional chambers containing food, furniture, and other items needed for the journey to the afterlife. Even after the Pharaohs switched to building pyramids and later rock-cut tombs, mastabas continued to be used by lower-ranking government officials and private citizens for more than a thousand years.

The first Egyptian pyramid, the Stepped Pyramid at Saqqara, was built around 2650 B.C.E. for the Third Dynasty pharaoh Djoser, who ruled from 2668-2649 B.C.E. Originally built as a mastaba, the tomb was successively expanded by stacking smaller mastabas atop one another, creating a six-tiered structure 58 metres tall. Traditionally attributed to the great architect and polymath Imhotep, the Stepped Pyramid was a milestone in architecture, being the earliest known structure of this scale to be built entirely out of stone. Inevitably, the experimental nature of this building material resulted in several architectural oddities throughout the pyramid and its surrounding temple complex. For example, in previous Egyptian temples columns were made of bundled tree trunks. When Imhotep attempted to recreate these structures in stone, he conservatively anchored them to the walls to ensure they would not topple over.

As with the earlier mastabas, the Stepped Pyramid itself is a solid structure, with the burial chambers and other rooms dug into the bedrock below. This underground complex is among the most extensive of any pyramid, totalling nearly six kilometres of tunnels, galleries, and shafts. It is also among the most lavishly decorated, with multiple carved reliefs of the pharaoh participating in various festivals and other activities and galleries lined in blue-green glazed tiles meant to emulate rolled-up reed mats. Among the spaces in the complex are the king’s burial chamber containing his stone sarcophagus, ancillary chambers for royal family members, and storerooms for grave goods – all built as vertical shafts sealed with massive stone caps to thwart grave robbers. Yet despite this, like all pyramids the Stepped Pyramid was extensively looted in antiquity, leaving almost none of the original grave goods for archaeologists to study.

It is not known exactly why Djoser and Imhotep decided to break with tradition and build such a radically innovative structure. Some Egyptologists believe that the expansion of the Step Pyramid was intended to make the structure visible from the nearby Ancient Egyptian capital of Memphis, projecting Djoser’s power and divine status to his subjects. Others, however, ascribe more spiritual significance to the pyramid shape. According to the Pyramid Texts, a series of funerary texts carved inside pyramids from the Fifth to Seventh Dynasties, the ancient Egyptians believed that the spirit of the deceased pharaoh ascended to the afterlife on a gigantic staircase – suggesting that the Stepped Pyramid was designed as a literal representation of this “stairway to heaven.” Still others, however, believe that the pyramid shape was intended to represent the spreading rays of the sun or the Benben, the primordial mound from which the creator god Atum was believed to have created the world. This theory further posits that the Stepped Pyramid was actually intended from the start to be a regular smooth-sided pyramid like those that came later but that this plan was interrupted by Djoser’s death – a view supported by the fact that the pyramid’s base is square rather than rectangular like those of traditional mastabas. Indeed, cosmic factors informed the construction of every pyramid, whose bases were often aligned with the points of the compass. All pyramids – and indeed, all royal tombs – were also built on the west bank of the Nile since this direction was associated with the setting sun and thus the entrance to the afterlife.

Whatever the case, this pioneering experiment kicked off a period of pyramid construction that would last nearly a thousand years. Djoser’s step pyramid was followed by three more, built by his Third Dynasty successors Sekhmekhet, Khaba, and Huni – though none of these have survived in nearly as good condition as the original. Then, around 2600 B.C.E, the Fourth Dynasty pharaoh Sneferu kicked off another surge of innovation when he attempted convert a stepped pyramid begun by his predecessor Huni at Meidum into a more classical smooth-sided pyramid. Unfortunately, right from the start the Meidum Pyramid was plagued with architectural errors. Not only was the original stepped pyramid core occupied the whole of the bedrock foundation, forcing Sneferu’s builders to stack the casing stones directly on the desert sand, but the tops of the steps were not horizontal and had been polished smooth. The result was a catastrophic failure in which the casing stones slid off the core during construction, causing the project to be abandoned. Whoopsie doodle.

Undeterred, Sneferu tried again, starting another pyramid at nearby Dahshur. But once again the project ran into problems. The structure, which was started at a 54 degree angle, soon began to show signs of instability. Thus, halfway through construction, the angle was reduced to 43 degrees, giving the structure its nickname of the “Bent Pyramid.” Yet despite its crooked appearance, the Bent Pyramid is unique in that the majority of its smooth Tura limestone casing remains intact, giving us an idea of what later pyramids might have looked like in their prime. With two failures but a wealth of practical experience under their belts, Sneferu’s builders tried once more and – proving that the third time really is the charm – finally succeeded. The Red Pyramid of Dahshur – named after the red granite used to construct its core – was the first successful smooth-sided pyramid in Egypt, and would set the blueprint for future constructions.

Now, at long last, we come to the most famous Egyptian pyramid of them all: the Great Pyramid of Giza, built by Sneferu’s son Khufu around 2570 B.C.E. In addition to being the largest pyramid ever constructed, the Great Pyramid is unique in another major way. Whereas all previous and subsequent pyramids feature burial chambers and tunnels built at or below ground level, the Great Pyramid is the only one in which the majority of these spaces are located within the main structure itself. While the Great Pyramid does possess a Subterranean Chamber or “pit”, located 27 metres below ground level, it was never finished. This chamber features a cramped horizontal tunnel extending 16 metres south before terminating in a dead end, as well as a small vertical hole called Perring’s Shaft some 30 metres deep. The latter was progressively excavated by 19th Century Egyptologists Giovanni Caviglia, Henry Salt, Richard Vyse, and John Perring in an unsuccessful attempt to locate the water-filled chamber described by Ancient Greek historian Herodotus. It is not known why the Subterranean Chamber was abandoned, with some Egyptologists like Ludwig Borchardt suggesting that the pyramid plans were altered partway through construction to place Khufu’s burial chamber higher up in the structure.

The Subterranean Chamber is accessed via the 100-metre-long Descending Passageway, which emerges 17 feet above ground level on the pyramid’s north face. Curiously, this entrance is not centred but lies 8 metres east of the pyramid’s centreline – a feature likely intended to fool grave robbers. The ceiling of the main entrance is framed by a distinctive set of chevron-shaped stone blocks, which distribute the structure’s weight and prevent the tunnel from collapsing. Today, however, tourists typically enter the Great Pyramid via the so-called Robber’s Tunnel, which begins 7 metres above ground level and runs horizontally for 27 metres until it intersects the Descending Passageway. This tunnel is traditionally attributed to the Abbasid Caliph Abu al-Rashid – better known as al-Ma’mun – who supposedly excavated it in the year 820 C.E. According to this story, al-Ma’mun – or possibly his father Haroun al-Rashid, the Caliph immortalized in One Thousand and One Nights – broke through into the pyramid’s sealed inner corridors and burial chambers only to find them empty, with not a scrap of treasure or even the mummified body of Khufu to be found. Since this time, al-Ma’mun’s shocking his discovery has provoked furious archaeological speculation: if the Great Pyramid never held Khufu’s body or grave goods, then what was it built for?

However, in recent years this account has been called into question. For one thing, the supposed date of the excavation does not line up with contemporary records of al-Ma’mun’s rule, which reveal that he spent the year 820 in the Caliphate’s capital of Baghdad. Indeed, al-Ma’mun only ever visited Cairo once – 12 years later in 832. Furthermore, nearly all known accounts of the excavation date from several centuries after the supposed events, and contain implausibly fantastical details. But perhaps the greatest strike against the al-Ma’mun story is the fact that by the time of his reign, tunnelling into the Great Pyramid would have been unnecessary. Though the entrance to the pyramid was originally concealed by limestone casing stones, by the early Middle Ages these stones had all been stripped off and used as building materials in Cairo. The entrance would thus have been exposed and well-known. Indeed, the ancient Greek historians Herodotus and Strabo both describe this entrance in great detail. Given this fact, al-Ma’mun would have had no reason to tunnel from the outside of the pyramid and could have started his excavations from within the Descending Passage. Far more likely is that the tunnel was dug by looters in antiquity and later became choked with rubble and forgotten. al-Ma’mun, if he ever excavated the pyramid at all, likely only rediscovered, re-excavated, and enlarged the original tunnel. As for how the looters knew where to dig, many grave robbers in Ancient Egypt are thought to have been workers who built the tombs themselves, and thus had intimate knowledge of their construction and security measures.

28 metres down from the main entrance, the Descending Passageway intersects with the Ascending Passageway, which rises at a 26º angle towards the south – into the heart of the pyramid. To prevent grave robbers from accessing this passage, its entrance was plugged with three enormous granite blocks, each around 1 metre cubed and weighing 2600 tons. These were likely concealed under limestone blocks matching the rest of the pyramid’s structure, leaving no evidence of the Ascending Passageway’s existence. Unable to dig through these much harder stones, the creators of the Robber’s Tunnel instead bypassed them entirely, digging a short tunnel up into the Ascending Passageway. 39 metres long, the Ascending Passageway is as short and narrow as the Descending Passageway, forcing visitors to hunch over as they climb. However, this tunnel soon opens up into the Grand Gallery, a spectacular granite-lined corridor 9 metres tall and 47 metres long. At the junction of the Ascending Passage and the Grand Gallery, visitors must step over a large hole in the floor, which marks the top of the so-called Well Shaft, a narrow tunnel that crookedly winds its way 50 metres down to the base of the Descending Passage, just above the entrance to the Subterranean Chamber. The Well Shaft is believed to have served as an escape tunnel for the pyramid workers, allowing them to exit the pyramid after placing the sealing stones at the entrance of the Ascending Passageway.

Directly south of the sealing stones, a horizontal corridor leads into the so-called “Queen’s Chamber”, a 5x11x6 metre granite-lined room located nearly in the middle of the pyramid and capped by a chevron-shaped stone-slab roof. The chamber is so-named because archaeologists originally assumed it was a burial chamber for one of Khufu’s wives. However, aside from a small niche in the east wall, the chamber is bare, with no sarcophagus or other funerary paraphernalia. The niche, originally only a metre deep, was significantly deepened by treasure hunters looking for additional hidden chambers.

Following the Grand Gallery upward, we arrive at the antechamber, the last line of defence for the King’s Burial Chamber. This space originally held three half-metre-thick granite portcullis stones, which were raised into a space in the ceiling during construction and lowered using ropes to seal off the room. However, the ceiling space was not then filled in, allowing grave robbers to climb over and bypass the portcullis stones and tunnel through the softer limestone into the King’s Chamber. Later, all three portcullis stones were broken up and carried out, clearing the antechamber.

And finally, we arrive at the largest and highest space in the pyramid: the King’s Chamber, where Emperor Napoleon is said to have spent his haunting night. The chamber, built of smooth granite blocks, measures 10x5x6 metres and contains a single object: a rectangular, solid granite sarcophagus. When the King’s Chamber was first entered in the early Middle Ages, this sarcophagus was found already broken open and emptied of all contents. In common with the rest of the pyramid, the walls of the chamber are bare and unadorned; indeed, funerary inscriptions would not become common in royal tombs until the Fifth Dynasty, 100 years later.

Above the King’s Chamber are a series of smaller chambers separated by horizontal granite slabs and capped by a chevron slab roof. Known as “Relieving Chambers”, these were likely built to relieve the stress on the chamber roof and prevent it from collapsing under the weight of the stone above. The first of these chambers has been known about since antiquity, being accessible from the Grand Gallery via a narrow passage. Then, in 1837, British Archaeologist Howard Vyse noticed a crack in the ceiling of this first chamber and inserted a narrow reed, revealing another empty space above. He and his workmen proceeded to cut through each subsequent slab with drills and dynamite – yes, really – revealing four additional chambers in all. Inside these spaces, Vyse discovered levelling lines, masons’ marks, and ancient graffiti spelling out the names of the work gangs who built the chamber – proving that no matter what the era, people cannot help but scrawl “I was here” wherever they go.

Another curious feature of the Great Pyramid is a system of four narrow shafts which rise at 45 degree angles from the north and south walls of the King and Queen’s Chambers, extending all the way to the pyramid’s outer walls.While the shafts in the King’s Chamber have long been known, those in the Queen’s Chamber were discovered in 1872 by British engineer Waynman Dixon, who, suspecting their existence, dug through the walls of the chamber to find them. Unlike the King’s Chamber shafts, however, the Queen’s Chamber shafts connect neither to the Queen’s Chamber itself nor the outside of the pyramid, and appear to be crudely carved and unfinished. One of these shafts also yielded some of the very few objects directly associated with the pyramid’s construction: a sphere of hard diorite stone thought to be a hammer or polishing tool, a bronze hook of unknown purpose, and a piece of cedar wood.

Initially, archaeologists assumed these structures were used for ventilation during construction and dubbed them “Air Shafts” – a name that persists to this day. However, the fact that both ends of the shafts are blocked by stone plugs casts doubt on this theory, and today it is generally believed that these structures served a spiritual function, allowing the pharaoh’s spirit to travel between the burial chamber and the land of the dead. This theory is supported by the fact that at the time of the pyramid’s construction, these shafts would have pointed towards the stars Alpha Draconis, Beta Ursa Minoris, and Sirius and the constellation Orion – all of which the Ancient Egyptians associated with the afterlife.

In recent years, archaeologists have attempted to explore the “Air Shafts” using various remote-controlled robots. The first of these, dubbed Upuat-2, was built by German engineer Rudolph Gantenbrink for the German Archaeological Institute, which conducted three expeditions between 1992 and 1993. The robot found the Queen’s Chamber southern shaft blocked by a stone block with a pair of bronze handles, preventing further exploration, while an attempted exploration of the northern shaft was abandoned due to the risk of the robot getting stuck in the roughly-carved tunnel. The next robot to explore the shafts was the National Geographic Society’s Pyramid Rover, which was designed by the company iRobot – yes, the creators of the Roomba robot vacuum – and equipped with a drill and a small fibre-optic camera that could be inserted through the resulting hole. In September 2002, Pyramid Rover succeeded in climbing the Queen’s Chamber’s northern shaft and drilling through the limestone plug at the end, behind which it discovered…another stone block, 19 centimetres away. Not only was the robot unable to penetrate further into the shaft, but its camera was only able to look directly ahead, preventing a thorough exploration of this small chamber. This limitation was overcome by the University of Leeds’ Djedi Project, whose robot was equipped with a flexible camera that could be twisted to peer around corners. In 2011, the Djedi robot inserted its camera through the hole drilled by Pyramid Rover and discovered painted hieroglyphs spelling out the number “121” – the length of the shaft in cubits, the standard Ancient Egyptian unit of measurement. The robot also revealed that the outside surfaces of the stone plugs are polished smooth, further supporting the theory that the shafts served a spiritual rather than utilitarian purpose.

But while this network of chambers, passages, and shafts is the most extensive of any Egyptian pyramid, there may be more waiting to be discovered. After all, these spaces make up a mere 1/7,400th of the Great Pyramid’s total volume. In 2015, a team of international researchers launched the Scan Pyramids Project in order to find any hitherto unknown chambers within the Great Pyramid. To avoid damaging the ancient monument, the Scan Pyramids team used a non-invasive technique called muon radiography, which makes use of subatomic particles called muons which are constantly streaming down from outer space. Areas of solid stone absorb more muons than hollow voids, meaning that by placing particle detectors beneath the pyramid, the team was able to map its internal structure. In 2017, after collecting 140 days’ worth of data, the team announced that they had discovered two major anomalies: a smaller void located directly behind the main entrance chevron stones, and a much larger space some 100 cubic metres in volume around 10 metres above the Grand Gallery. Due to its proximity to the pyramid’s outer surface, the team decided to focus on the first anomaly, and in March 2023 succeeded in penetrating it with a fibre-optic camera inserted through a gap between two stones, revealing a small corridor 2 metres tall by two metres tall and 9 metres long. Like the Relieving Chambers above the King’s Chamber, this space was likely built to redistribute structural loads away from the entrance and Descending Passageway. But the second space – which egyptologists have dubbed the “Big Void” – remains a mystery, its location deep preventing researchers from accessing it – for now, at least.

Despite these discoveries, however, many mysteries remain. Was Khufu actually buried in his pyramid, only for his mummy and grave goods to be looted in antiquity? Or were the pyramid’s inner chambers sealed empty? If so, why? What was the purpose of the Queen’s Chamber? Why was the Subterranean Chamber abandoned and the burial chambers moved upwards into the heart of the pyramid? Unfortunately few records from Khufu’s reign survive, while subsequent pyramids, like those built next door by Khufu’s son Khafre and his grandson Menkaure, provide few answers, being built in the old style with solid bodies and burial chambers at or below ground level.

Whatever the case, with the construction of Menkaure’s tomb, the age of pyramid building reached its high-water mark. Subsequent Old Kingdom pyramids, such as those of Sahoure, Neferikare, and Niouserre, were more hastily built from poorer-quality materials like mud brick encased in stone, and are now almost all in ruins – either due to natural erosion or the plundering of stone for construction projects by the Romans or Ottomans. Unlike the tombs of Khufu, Khafre, and Menkaure, however, many later pyramids like those of Ounas, Teti, and Pepi I, were lavishly decorated, their burial chambers adorned with extensive funerary inscriptions known as the Pyramid Texts. Pyramid building largely petered out by the end of the Old Kingdom, though the Middle Kingdom saw a brief revival of the practice lasting from the reign of Amenemhat in the 12th Dynasty to Khendjer in the 13th. However, by the start of the New Kingdom in the 16th Century B.C.E, the pharaohs had abandoned above-ground mastabas and pyramids in favour of rock-cut tombs at sites like the Valley of the Kings, which were much easier to conceal and guard from would-be looters. It is here that some of the most famous pharaohs, including Ramses II and Tutankhamun, were buried.

But this was not quite the end for Egyptian pyramids, for nearly 1000 years after the last Middle Kingdom pyramid was built, the form enjoyed one last major revival. In 744 B.C.E, Egypt came under the control of the Kingdom of Kush, based in Nubia in what is now southern Egypt and Northern Sudan. Between 300 B.C.E and 300 C.E., the Kushites built over 225 pyramid-shaped tombs around the Kingdom’s capitals of Kerma, Napata, and Meroë. Though inspired by earlier classical Egyptian architecture, the Nubian pyramids are significantly smaller – the largest topping out at 30 metres tall – and rise at much steeper angles – 70 degrees compared to 40 for older pyramids. Like Old Kingdom rock-cut tombs, the burial chambers are lined with plaster and adorned with painted scenes depicting scenes from the life of the deceased. Sadly, while many of these pyramids survived antiquity in extremely good condition, over 40 were demolished in the 1830s by Italian treasure hunter Guiseppe Ferlini, who blew them apart with dynamite searching for jewelry and other grave goods.

This, of course, is only a brief overview of some of the ancient Egyptians’ most impressive archaeological achievements and the lingering questions they pose – questions which remind us that despite all we have learned about this ancient civilization, the land of the Nile has yet to give up all its secrets.

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