Most people know the pyramids were built as grand tombs for pharaohs, designed to support their journey to the afterlife. The Great Pyramid of Giza, for example, was constructed for King Khufu. But the pyramid-building tradition itself began earlier, with the Step Pyramid of Djoser at Saqqara, built around 4,700 years ago for one of the rulers of Egypt’s Third Dynasty.

The pyramid rises in seven distinct tiers and reaches about 200 feet in height. For the ancient Egyptians, it appears to have functioned as a large-scale experiment, a way to refine construction techniques before undertaking more ambitious projects. Beneath the structure, however, lies a network of tunnels extending roughly three and a half miles, which some researchers believe may have been part of an advanced water management system.

The pyramid is surrounded by what is known as the dry moat, a connected ditch up to 164 feet wide and nearly two miles long. It forms a rectangular frame around the pyramid with an average depth of about 65 feet. The volume of earth and rock removed to create it would have been roughly ten times the volume of the pyramid itself.

For a long time, researchers assumed the moat was simply a quarry where stone and clay were extracted for construction. A closer look raises questions about that explanation. The moat is narrow and deep, which would make quarrying impractical, and its design does not match known patterns of ancient Egyptian quarrying. Some sections are even covered by rock ceilings, which would make mining nearly impossible.

Another theory suggests the moat had spiritual significance, perhaps a sacred space where noble spirits could gather to serve the deceased king. Some wall niches support this idea. Most researchers, however, believe this function developed later, well after the complex was built for Djoser.

In 2020, a researcher proposed that the moat was designed to collect and manage water, particularly after heavy rainfall. The location supports this idea, as the area would have been prone to flooding from rain flowing off nearby plains. This could also explain why the moat was not used for new burials until later, when the climate became drier and less prone to flooding.

The moat appears to be part of a larger hydraulic system within the Djoser complex. It contains several chambers carefully carved into the rock, connected by tunnels. These chambers may have been part of a water treatment system, with water flowing from one chamber to another and becoming cleaner as it moved.

Some researchers believe the water from the moat may have powered a hydraulic lifting system used to raise heavy stones during construction. The idea is that water, after being filtered and purified, flowed into deep shafts. A large float, possibly made of wood, would rise as the shaft filled with water, lifting stones to the needed height. After a stone was placed, the water would be drained, lowering the platform for the next load.

This system could have made construction faster and more efficient, reducing the need for large work crews. It suggests the ancient Egyptians were already thinking about working smarter rather than harder.

Not everyone is convinced. Some experts argue the area around the Step Pyramid would not have collected enough seasonal rainwater to power such a system. One main theory suggests a nearby lake may have existed in the past, filling after rainy periods and supplying water to the complex. But no ancient Egyptian writings mention such a lake, so this remains speculative.

There is also the question of labor. Some experts point out that building the hydraulic device itself would have required far more work than moving the blocks using conventional human power. The stones used in the Step Pyramid weighed on average about 300 kilograms each, considerably lighter than the blocks over two and a half tons used in later pyramids like that of Khafre.

Even if the water-lifting theory is set aside, the construction of the pyramid still needs explanation. Originally, Djoser’s tomb was planned as a simple mastaba, a rectangular structure with a flat roof and sloped sides, common in earlier periods. After the initial mastaba was completed, the builders decided to expand it by adding layers on top. They continued adding layers until the structure reached six distinct tiers, each smaller than the one below. This was likely done using ramps to move the heavy stones, rather than a water-powered elevator.

Much about the Step Pyramid remains unknown. More research is needed to understand how the complex functioned and whether the hydraulic theories are correct. The idea of using water to assist in construction adds a new dimension to our understanding of ancient Egyptian engineering and highlights the ingenuity of the builders who used the landscape and natural resources to create one of history’s most famous monuments.

The Step Pyramid is not the only source of debate among researchers. In 1898, excavations at Saqqara uncovered a small wooden object that would later become known as the Saqqara Bird. The artifact, made of sycamore wood, has a wingspan of seven inches and weighs about 40 grams. It has a beak and eyes, resembling a falcon, the symbol of the god Horus. Its tail is unusual, square-shaped and standing upright, and it appears to have a missing piece.

Several explanations have been offered over the years. Some suggest it was a ceremonial object, a toy for a wealthy child, a type of boomerang, or a weather vane. The weather vane theory was dismissed because the object has no holes or markings suitable for hanging, apart from those made later by the Cairo Museum for display purposes.

In the late twentieth century, Egyptologist Dr. Khalil Messiha proposed that the object might be a model of a monoplane. He believed it was missing a horizontal tail surface and that its wings were positioned at right angles, similar to modern aircraft, capable of generating aerodynamic lift. He also noted that it was common in that period to place miniature models of technological inventions in tombs.

To test the theory, hang glider designer Martin Gregory built a similar model from balsa wood and concluded that even with the missing tail, it did not fly well. Later, a History Channel program brought in an aerodynamics expert who built another version and tested it under conditions similar to those in Egypt. That expert was impressed by the small aircraft’s capabilities.

If the ancient Egyptians did create a prototype aircraft, it would be an example of an out-of-place artifact, an object far ahead of its time technologically. The Saqqara Bird is not the only artifact that raises such questions.

In 1901, divers recovered the Antikythera mechanism from a shipwreck near the Greek island of Antikythera. The bronze device, dating to around 100 BC, has been called the world’s first analog computer. It could determine the positions of the sun, moon, planets, and stars, as well as moon phases, eclipse dates, and the moon’s movement speed. No one knows who made it, where, or how, but it is remarkably accurate and advanced for its time.

Around 4,000 years ago, both the Minoans in Crete and the Indus Valley civilization developed early flush toilets. One Minoan toilet found in the Palace of Knossos had a wooden seat placed over a tunnel that directed water from a rooftop tank into an underground drain. Other versions used water poured from jars. Such amenities were likely limited to the wealthiest households.

Automatic doors, which seem like a modern convenience, have older roots. In the first century AD, mathematician and engineer Hero of Alexandria created a hydraulic system for opening and closing temple doors. A fire beneath a copper vessel half-filled with water would heat the water, causing it to move into containers that acted as counterweights. The containers would descend and pull ropes. Unlike modern automatic doors, Hero’s system took hours to open and could not be stopped once started. Doors were opened once daily before people entered the temple, adding an element of mystery to ceremonies.

A clay jar discovered in Baghdad in 1938, dating back about 2,000 years, may have been an early battery. When filled with a weak acid like vinegar, it produced about one volt of electricity. Some theories suggest it was used for electroplating objects with precious metals, while others believe it held sacred scrolls.

Leonardo da Vinci designed a glass lens with a funnel on one side in 1508, intended to be worn with water inside to improve vision. About a century later, French scientist René Descartes refined the idea by suggesting the lens lie directly on the cornea. These early contact lenses were impractical, as blinking was impossible. It was not until more than two centuries later that glassmaking techniques allowed for lenses that fit the eye and allowed blinking. Those lenses were heavy and did not let the eye breathe. In the 1940s, plastic lenses became available, and in 1948, an English optical technician accidentally polished a plastic lens that stayed in place while covering only the cornea.

In 1858, the first transatlantic telegraph cable reduced message delivery time from about ten days by ship to hours. Queen Victoria sent the first message. The cable failed after a few weeks and took years to restore.

The construction methods of the Egyptian pyramids remain a subject of ongoing study. The most prominent theory involves the use of ramps. Builders would construct a sloping, winding mound of brick, earth, and sand around the pyramid, extending it as the structure grew. According to the ancient Greek historian Herodotus, workers used sledges, rollers, and levers to move the massive blocks. He also claimed the Great Pyramid took 20 years to build and involved 100,000 men. Those workers were likely farmers who worked on the pyramids during the Nile flood season when fields were underwater.

Later research in the late twentieth century suggested the workforce may have been smaller and more permanent. Some experts proposed a crew of around 20,000 workers, supported by bakers, doctors, and spiritual leaders. Another theory suggested the pyramids were built from the top down, using isolated hills as quarries, with engineers gradually transforming them into pyramids. Some researchers found this idea plausible in certain cases.

An unfinished obelisk in Egypt raises similar questions. Some experts suggest workers used hand tools to shape it. One researcher noted that the pattern left by the shaping tool is remarkably precise and even, which would be unlikely with ordinary manual work. The horizontal lines on the trench walls are consistent with a tool that paused during material removal. The same researcher suggested the ancient Egyptians may have had access to more advanced technology than previously assumed.

Ancient Egyptians are also credited with several everyday inventions. They created portable mirrors decorated with engravings and drawings. They devised early toothbrushes and toothpaste. One mixture included rock salt, mint, dried iris petals, and pepper, which some modern dentists tested successfully. Another recipe used ground ash but lacked mint, so it did little for breath freshness. Egyptians also made early breath mints from spices like cinnamon mixed with honey.

Egyptians developed furniture decoration using various ink colors and created different types of paper. They wove small rugs from papyrus. They made small figurines of cats, dogs, and people from materials ranging from sun-dried clay to pure gold, depending on the owner’s wealth.

In agriculture, Egyptians used ox-drawn plows of two types: heavy plows that cut deep furrows and lighter plows that followed to turn the soil. After plowing, they broke up soil clods, planted seeds in rows, and walked cattle across the field to press seeds into the furrows. Their irrigation techniques were advanced enough that later cultures, including the Greeks and Romans, adopted them.

Egyptian architecture also included decorated channels for water distribution and the Great Temple at Abu Simbel, designed so sunlight enters twice a year to illuminate statues of Ramses. The stepped arch contributed to the stability of structures like the Great Pyramid. Egyptians built grand halls and inner sanctuaries, some of which served as astronomical observatories.

In recent years, researchers using satellite radar technology reported finding structures beneath the Pyramid of Khafre. The Italian and Scottish team, known as the Khafre Project, claimed to have detected eight large vertical structures, possibly shafts or wells, extending across an area of about 6,500 feet and descending nearly 2,000 feet underground. These cylindrical structures are surrounded by spiral pathways and connected to two large chambers, each more than 260 feet wide. The team suggested similar access points may exist beneath all three pyramids at Giza, possibly linking them in a hidden network of tunnels and rooms.

Some team members proposed that these structures might correspond to the legendary Halls of Amenti, a place in ancient Egyptian mythology where people undergo a three-day test confronting their greatest fears.

The researchers used two satellites orbiting 420 miles above Earth, sending radar signals to the Giza plateau. These signals were compiled into a three-dimensional model of the underground layout. Using synthetic aperture radar, which can penetrate stone, the team also reported detecting five small chamber-like structures within the pyramid. One of these rooms contained a sarcophagus previously thought to be the tomb of Pharaoh Khafre, but researchers now believe his actual burial site is elsewhere. The chambers appear to be arranged in the center of the pyramid and connected by underground passages leading deeper beneath the structure. Some of these may date back around 4,500 years.

The claims have been met with skepticism. Many archaeologists and radar experts have questioned whether the technology used is sophisticated enough to produce such detailed images of the underground. Some suggested the smaller chambers near the surface could be natural formations. Others dismissed the radar methods as unproven. The findings have also revived discussion about the Hall of Records, a legendary chamber said to contain the wisdom of early Egyptians. The team hopes to begin excavation, but obtaining approval from Egyptian authorities is reportedly difficult.

In a separate project, researchers used electrical resistivity tomography and ground-penetrating radar to investigate an unexplored area in the Western Cemetery at Giza. They detected an L-shaped anomaly about six and a half feet below the surface, at least 33 feet long. The structure appeared to have been filled with sand after construction. It was classified as a high-resistance anomaly, meaning it did not form naturally due to its sharp shape. The feature may be a missing burial chamber, an offering chapel, or an unknown type of structure. Excavations are underway, though the fragile nature of the ancient site requires careful handling.

Historical records show that tomb robbery was common in ancient Egypt. Many famous tombs, including those at Giza, Saqqara, and the Valley of the Kings, were plundered. Thieves dug secret tunnels, bribed or threatened workers, and broke open sarcophagi to steal gold, jewelry, and artifacts. The Valley of the Kings, despite its hidden tombs, heavy stone blocks, false doors, traps, and written curses, was nearly emptied within a hundred years of being sealed. Even King Tutankhamun’s tomb was broken into twice in ancient times.

Pharaohs of the New Kingdom built hidden, unmarked tombs in an attempt to deter thieves, with limited success. Some rulers, including Ramses II, were moved in secret to protect their bodies. Thieves were often skilled and organized, sometimes the very workers who built the tombs and knew where the entrances were. They worked quickly, often within years of a tomb’s sealing, and sometimes dug through walls, floors, and ceilings.

The looting went beyond gold. Detailed records of what was buried and where allow archaeologists to see what is missing, which is often everything of value. Most stolen artifacts disappear into private collections where they cannot be studied. Some countries have passed laws to recover historical artifacts. Italy requires proof of legal acquisition for ancient Roman items. China actively tracks stolen artifacts. Egypt has passed laws criminalizing private ownership of ancient artifacts. Other countries, including the United States, the United Kingdom, Germany, and Switzerland, have fewer restrictions.

The British Museum holds many artifacts acquired during colonial expansion, such as the Rosetta Stone, taken from Egypt by Napoleon’s army and then seized by the British. Egypt has asked for its return for years without success. The Parthenon Marbles, taken from Athens by a British lord in the nineteenth century, are similarly contested. European explorers also removed large numbers of Central American artifacts from Maya and Aztec temples, and Mexico has fought for their return.

Whether the newly discovered underground chamber at Giza has survived the attention of tomb robbers remains unknown. It is possible it could be one of the few places untouched for thousands of years. Archaeologists continue to investigate, hoping to learn more about the people who built the pyramids and the world they lived in.