"I have seen the high walls of Babylon where chariots could run, and the statue of Zeus on the banks of the Alpheios River. The Hanging Gardens and the Colossus of the sun god Helios as well. I have seen the awe of the pyramids so vast that words cannot suffice, and the great mausoleum of Mausolos, but when I beheld the temple of the goddess Artemis, which seemed to touch the clouds, the others lost their light. Even the sun, from outside Olympus, has seen nothing to match it."
In the 2nd century B.C., the Greek poet Antipatros introduced in his poem seven of the most wondrous structures. The term "the Seven Wonders of the World" came from this. It refers to the grand architecture and works of art achieved in the ancient Hellenistic civilization that then meant the world, but now all have vanished and only the pyramids remain. The poet ranked the temple of Artemis first, but considering what has survived to this day, the undisputed greatest wonder is the pyramids.
Scientists have uncovered the secret of the pyramids built 4,500 years ago. The clue was the route used to move the massive stones. Vicente Luis Rosell Roch of Spain said, "The ancient Egyptians built a passage that spiraled up along the pyramid's edges instead of using an external ramp, allowing them to stack heavy stone blocks in a short time," in an article published in March in the international journal "Nature Press Journal Heritage Science."
Installing stone-moving routes along the edges
The pyramids Antipatros spoke of were likely the tomb of Khufu, king of the 4th Dynasty of ancient Egypt, built in the 26th century B.C. Records say that at completion it stood 147 meters tall with each side of the base measuring 230 meters, the largest among the pyramids, hence its name, the Great Pyramid. The Great Pyramid of Giza has long been an architectural mystery. In an age without wheeled carts, iron tools, or pulleys, stacking 2.3 million massive stone blocks weighing up to 17 tons within 20 to 27 years, the span of Khufu's reign, was close to impossible. It was not unreasonable that films and novels depicted it as being built by aliens.
Rosell Roch is a computer engineer with a Ph.D. in pattern recognition and artificial intelligence (AI) from the Universitat Politècnica de València in Spain. In 2020, while watching a documentary on the construction of the Great Pyramid, he thought each existing explanation had contradictions. The most representative explanation is the external ramp. The simple idea of building a road consolidation to the pyramid and stacking stones is easy to understand, but the problem was that the route for moving stones became too steep as the pyramid rose.
He immediately sketched an alternative on paper. He thought a spiral route rising along the pyramid's edges could keep the gradient constant. He then built a 3D (three-dimensional) model of the pyramid construction site on a computer and simulated a model called the "integrated edge ramp."
The principle is simple. As each course is laid, some portions along the edges are left unfilled with stone and covered with sand, soil, or planks to create a 3.8-meter-wide spiral ramp for moving blocks. This keeps the gradient at about 7 degrees, and with 24 to 25 people pulling, a standard stone block of nearly 3 tons on a sled could be hauled up by rope. Once the pyramid is completed and the edge transport routes are filled, a perfect square pyramid appears from the outside. At first he envisioned a single ramp, but later added routes on all four faces of the pyramid to increase transport efficiency.
The simulation showed that a stone block could be set every 4 to 6 minutes. At this pace, the Great Pyramid could be completed in 14 to 21 years. But considering quarrying and workers' rest times, the total construction period extends to 20 to 27 years. It was once thought that slaves were driven without rest to build the pyramids, but recent views hold that most workers were skilled artisans and laborers. Accordingly, adequate rest periods were likely provided.
Packing sand with water, using wooden pulleys
The simulation was not a mere thought experiment but was conducted on the basis of prior findings. In 2014, physicists at the University of Amsterdam in the Netherlands reported that sprinkling water on sandy paths would allow stone blocks to be transported to the pyramids using sleds without wheels. When water is sprinkled on sand, the grains consolidate through capillary action. This makes it about twice as firm as dry sand. As a result, even when pulling a sled loaded with stone, sand does not pile up in front and the sled slides more easily.
The physicists' results also match Egyptian wall paintings. In the tomb mural of Djehutihotep, a provincial governor of the 12th Dynasty of ancient Egypt in the 19th century B.C., 172 men are shown pulling a sled carrying a giant statue with ropes. In the mural, however, one person is not holding a rope but sprinkling water on the sand in front of the statue. Today's physicists' findings were already known to the ancient Egyptians. The Amsterdam team estimated that by wetting the sand appropriately, the number of people needed to move a sled loaded with stone could be halved.
They also applied a rudimentary pulley principle. In 2018, a joint team from the University of Liverpool in the United Kingdom and the French Institute of Oriental Archaeology announced that stone blocks could be moved up to the pyramid from an external ramp by winding ropes around wooden posts. The team excavated a ramp with stairs along both edges and holes for wooden stakes at the Hatnub quarry in eastern Egypt. By the same method at the pyramid site, they said, ropes were looped over stakes and workers on the stairs pulled from above and below. This suggested that steeper ramps could have been used at the construction site. The results showed that by pulling ropes over wooden-post pulleys, heavy stone blocks could be hauled up even on steep paths with an 11-degree gradient.
In the computer simulation, Rosell Roch assumed that water was sprinkled on the edge ramps and ropes were looped around wooden posts to haul the stones. At the corners where two faces of the pyramid meet, he widened the route to provide space to rotate the sled carrying stone by 90 degrees. He also inferred that ropes were pulled using the wooden posts as pulleys to change the sled's direction.
A hidden space found by cosmic particles
The spiral edge-ramp model also matches the observations from the 2023 ScanPyramids international collaborative research project. The team then used muons—the elementary particles that make up matter—to peer through the pyramid as X-rays do through the human body.
Muons, like electrons, penetrate well through matter. Scientists can locate voids by comparing the number of muons detected inside the pyramid. More muons are detected in empty spaces than in stone. The edge ramp posited by Rosell Roch was found to have the same gradient as the internal voids detected by muon measurements, suggesting a close connection.
Inside the Great Pyramid, there is an underground stone chamber with a sarcophagus, the Queen's Chamber in the middle, and above it the King's Chamber, stacked one above another. Between the Queen's Chamber and the King's Chamber stretches the Grand Gallery, 8 meters high and 2 meters wide, for 47 meters. The ScanPyramids team in 2016 and 2017 discovered previously unknown spaces above the pyramid's north entrance and directly above the Grand Gallery, respectively.
The ScanPyramids team reported that the secret space just behind the pyramid's north entrance, identified through muon measurements, is 2 meters by 2 meters and 9 meters long. The team inserted an endoscope and confirmed that the top is an arched structure.
French architect Jean-Pierre Houdin argued that there is a spiral passage inside the pyramid like a tunnel for cars. He also considered the space found by muon probing to be part of it. But scientists think the secret spaces inside the Great Pyramid are not passages but were created to distribute the weight of the entrance or of rooms or spaces yet to be discovered.
Rosell Roch's computer simulation model likewise explained that this hidden space was deliberately left empty as a structural buffer zone to withstand the enormous loads generated when heavy stones were moved along the edge ramps. With physics and space science, plus computer engineering and AI all brought to bear, the secrets of the Great Pyramid—built with only copper chisels, ropes, and wooden sleds—are being revealed.
References
npj Heritage Science (2026), DOI: https://doi.org/10.1038/s40494-026-02405-x
Nature Communications (2023), DOI: https://doi.org/10.1038/s41467-023-36351-0
University of Liverpool (2018), https://news.liverpool.ac.uk/2018/11/02/ancient-quarry-ramp-system-may-have-helped-workers-build-egypts-great-pyramids/
Physical Review Letters (2014), DOI: https://doi.org/10.1103/PhysRevLett.112.175502