A groundbreaking study has shed new light on the remarkable engineering prowess of Neolithic builders who constructed the Menga dolmen in southern Spain nearly 6000 years ago.
The research, published in the journal Science Advances, found that the monument’s architects used advanced principles of physics, geometry, and material science to build the massive structure, which has allowed it to endure for millennia.
The findings overturned long-held views that Neolithic construction techniques were primitive, suggesting instead that the megalith builders had a sophisticated understanding of forces, angles, and the properties of stone.
Lead author José Antonio Lozano Rodríguez said the study “runs entirely counter to the idea of ‘primitiveness’ or ‘rudeness’ that for a long time has underpinned both the popular and scientific understanding of Neolithic societies.”
About the Menga Dolmen
Located near Antequera in Andalusia, the Menga dolmen is the largest and oldest of the region’s prehistoric megalithic structures. Built between 3800 and 3600 BCE, the monument is a prime example of a dolmen or single-chamber megalithic tomb.
The scale and complexity of Menga is staggering. Its chamber stretches nearly 25 meters (82 ft) in length, varies between 2.7 and 3.5 meters in height, and ranges from 3.5 to 5.4 meters in width. The structure comprises 32 upright megaliths supporting five massive capstones, with a total mass of around 1140 metric tons. The enormous capstone alone weighs approximately 150 tons, making it the heaviest stone block in any European prehistoric monument.
Above: Location and interior views of the Menga dolmen in Antequera, Spain. (Source: Early science and colossal stone engineering in Menga, a Neolithic dolmen (Antequera, Spain))“
Through a multidisciplinary geoarchaeological analysis, the researchers made several discoveries that transformed our understanding of how this megalithic marvel was built.
Polarity Analysis of Stones
By studying the orientation of shell fossils and imprints preserved in the megaliths, the team determined that the massive stone blocks were transported and placed inside the monument as it was being built. This contradicts previous assumptions that they were manoeuvred into place using external ramps. The authors say this ingenious technique avoided the need for large ramps, which could have damaged the relatively soft limestone and sandstone blocks.
Precise Angles and Interlocking Design
The upright megaliths that form Menga’s chamber walls are positioned at slight angles, leaning inward, to create a trapezoidal cross-section. The team found that the stones’ sides were trimmed to angles around 85°-87°, just off-vertical, causing the chamber to narrow towards the top.
Additionally, the stones were made to interlock with each other through precisely cut concave facets on their sides. These facets allow the rocks to lean against each other at angles of 77°-80°, transferring their weight from one to the next. Together, these two features – the inward lean and interlocking angles – make the uprights “self-supporting” and allow them to bear the colossal weight of the capstones in a stable configuration.
Foundations Embedded in Bedrock
Perhaps most remarkably, the researchers found that the upright stones are embedded into the underlying bedrock to astonishing depths – up to 2 meters or about one-third of their total height. The builders excavated deep trenches to create a “foundation box” that anchors the entire structure into the ground.
These three key findings – the inside-out construction, the angling of the uprights, and the profoundly sunken foundations – show that Menga’s creators used advanced engineering principles to ensure the monument’s stability and longevity. But what exactly were these principles? Let’s examine them one by one.
Engineering Principles Used
Physics: Friction, Center of Mass, and Stability Moving and raising the massive blocks that makeup Menga required a keen understanding of forces and motion—in essence, a practical grasp of Newtonian physics millennia before Newton.
To transport the blocks from quarries up to a kilometre away, the builders likely used sledges or rollers on carefully prepared trackways to minimize friction. Placing the 150-ton capstone at the end without breaking it would have required exceptional control.
The researchers believe the strategy of embedding the uprights deep into the bedrock reflects an intuitive understanding of the centre of mass and stability. By sinking the foundations, builders maximized the structure’s strength and created resistance to seismic vibrations – a technique still used in modern construction.
“This reveals that the architects of this dolmen had an intuitive understanding of the benefits of getting the center of gravity of these large stones as low as possible,” said co-author Adolfo Arrieta.
Geometry: Angles and Surveying The precise angles at which the uprights are positioned – around 85° off vertical for the chamber walls and 77°-80° for the interlocking facets – point to a sophisticated use of geometry and surveying in Menga’s design.
The researchers believe the monument’s engineers used a “plumb bob” tool and triangulation techniques to position the blocks at the desired angles, effectively employing trigonometry long before its formal mathematical development. The trapezoidal cross-section created by the angled uprights and the interlocking concave facets is critical to the structure’s ability to support the weight of the enormous capstones.
Material Science: Selection and Placement of Stones
The builders demonstrated a keen understanding of the properties of different rock types when selecting and placing megaliths. The monument incorporates a variety of local stones, including limestone, sandstone, and conglomerate, some of which are harder than others.
Fossils and mineral layering reveal that the builders consistently oriented the blocks with their natural bedding planes facing inwards into the chamber. The authors say this was intentionally done to prevent erosion and water infiltration, mainly the softer limestone, that could weaken the stones.
Intriguingly, the enormous capstone, weighing 150 tons, is made of a much harder conglomerate rock than the others. Its upper surface was carved into a subtle arch profile, which the authors say makes it act as a “keystone” to distribute forces into the supporting uprights – the first known instance of this sophisticated technique.
This research shows that the Neolithic architects and engineers who built Menga had a remarkable understanding of physics, geometry, and stone properties, which they used to create an enduring megalithic monument of astounding scale and complexity.
As Rodríguez and colleagues write: “Menga is a unique example of creative genius and early science among Neolithic societies…designed as a completely original engineering project, for which we know of no precedents in Iberia.”
The team says the findings suggest an exceptional convergence of knowledge and skills flourished in prehistoric Iberia nearly 6000 years ago. This early scientific and engineering prowess would not be seen again in the archaeological record for thousands of years, making Menga an extraordinary testament to the abilities of its long-anonymous builders.
Far from primitive, these ancient architects were masters of a precocious “megalithic science” of design and construction – one that allowed them to transform stone into a monument that has endured for nearly six millennia and still inspires wonder today.
TL;DR:
- A new study shows that neolithic engineers used principles of physics, geometry, and material science to build Spain’s Menga dolmen ~6,000 years ago.
- Precise angles, interlocking joints & deep bedrock foundations provided stability for the 32 massive stones.
- Builders intuitively used concepts of friction, the centre of mass, and force distribution to move and place huge blocks.
- Stones were selected & oriented based on hardness and natural bedding to prevent erosion.
- Findings overturn “primitive” stereotypes and show that the monument is a marvel of prehistoric engineering.