There are numerous theories about how Stonehenge, the prehistoric megalithic structure in Wiltshire in the United Kingdom was constructed, but one question persists: How did our ancestors build such a monument? Some archaeologists have sought clues in the distant past, and a recent study may actually provide insight. As it turns out, the answer was in Spain all along, at another stone monument built 1,000 years earlier.
The Menga dolmen. Located in Antequera, in southern Spain, the Menga dolmen is one of the most impressive and ancient megalithic monuments in Europe, dating back to around 3,500 B.C. Its significance lies in its incredible size (it features an 82-foot burial chamber made of enormous stones weighing tons) and its unusual orientation towards the Peña de los Enamorados (“The Lover’s Rock”) mountain, which sets it apart from other dolmens that are usually aligned with solar events.
The Menga dolmen is a unique construction, a masterpiece of prehistoric architecture. With a combined weight of approximately 1,140 tons, it’s heavier than two Boeing 747 aircraft loaded with passengers. Therein lies part of the mystery and magic of this type of construction. Now, a recent study sheds light on the knowledge and techniques employed in building similar structures.
The new study. Recently published in the journal Science Advances, the study reveals that the Menga dolmen was built with an extraordinary level of scientific understanding. “I’ve always been amazed by the engineering skills needed to build this dolmen,” Michael Parker Pearson, an archaeologist at University College London, says. “This paper reveals just how precisely that has to have been done, with an extraordinary eye on dimensions and angles. With such big stones, they could not have afforded to make mistakes when maneuvering them into position.”
José Antonio Lozano Rodríguez, a geologist at the Spanish Institute of Oceanography and co-author of the study, told Interesting Engineering, “Initially, what most sparked my interest in the Menga dolmen was its monumentality. Entering its interior and contemplating such a colossal monument from the Neolithic period, aroused my curiosity to learn more about this dolmen.”
A recreation of the proposed process of placing the vertical stones.
How to move tons of stone. What the researchers apparently did was dive into what’s known as geoarchaeological analysis of the site, examining laser and visual scans from previous excavations. They also analyzed ethnographic descriptions of the construction techniques and topography of the area.
Once the data was collected, the team deduced something previously unknown: the construction process of the Neolithic engineers. They started from known facts. For example, a previous study had already established that the stones came from a quarry located less than a mile away, at a strategically higher altitude than the Menga dolmen. How? Experts think that the builders transported the stones using sledges on a track made of wooden beams, which implies a knowledge of friction, acceleration, and center of mass.
A recreation of the proposed process of placing the vertical stones inside the dolmen.
Carving the stones was key. As the paper explains, when constructing the ancient site, the builders positioned the stones that formed the walls and columns vertically, leaving up to a third of each stone underground. They likely accomplished this by using counterweights and ramps to account for the soft and easily damaged nature of the sandstone rock.
The study suggests that the stones in the wall were carved to interlock and lean against each other, increasing the stability of the structure. According to study co-author Leonardo García Sanjuán, an archaeologist at the University of Seville in Spain, “These people had no blueprints to work with, nor, as far as we know, any previous experience at building something like this,” adding, “There’s no way you could do that without at least a basic working knowledge of science.”
The principle of arch, used for the first time. The researchers found that the walls of the chamber slope slightly inward, forming angles of between 84/85 degrees. This makes the upper part of the chamber narrower than the trapezoidal-shaped lower part. In this respect, the largest of the five capstones was carved in a way that creates a rudimentary arch, with its center higher than its sides, to better distribute stress.
This is no coincidence. According to the research team, “To the best of our knowledge, this is the first time that the principle of the arch has been documented in human history.” Constructing the chamber partially underground allowed the capstones to be placed on top without needing to lift them very high. The researchers also excavated the ground inside the chamber to lower the floor level, while covering the outside with earth to provide further insulation and stability.
Bottom line. The findings reveal a significant shift in our understanding of Neolithic architecture. This study not only sheds light on the construction of the Menga dolmen but also provides insights into later works and monuments such as Stonehenge and the Step Pyramid of Djoser in Egypt.
As a result, experts can only describe the mastery of these concepts as science: “We have to call it science. We’ve never talked about Neolithic science before, only because we are too arrogant to think that these people could do science the way we do it,” García Sanjuán said.
He adds: “If any engineer today tried to build Menga with the resources that existed 6,000 years ago, I don’t think they could do it.”
Image | Pouya Jabbarisani (via Unsplash)
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