Colossal Stone Monument Built 1,000 Years Before Stonehenge Shows Neolithic Engineers Understood Science
A recent study of the Menga dolmen in Spain reveals complex construction techniques used roughly 6,000 years ago
The Step Pyramid of Djoser, one of Egypt’s oldest stone buildings, and the iconic Stonehenge in England stand out of some of the crowning achievements of ancient builders. But 1,000 years before either of those was constructed, Neolithic people in present-day Spain built a colossal stone chamber that included a 150-ton capstone—roughly five times the weight of the heaviest megalith at Stonehenge.
Dating to between 3600 and 3800 B.C.E., this early structure, known as the Menga dolmen, was one of the largest megalithic monuments of ancient Europe. And, according to an analysis published in the journal Science Advances last week, it was constructed with an extraordinary level of scientific understanding.
“I’ve always been amazed by the engineering skills needed to build this dolmen,” says Michael Parker Pearson, an archaeologist at University College London who was not involved in the study, to Nature News’ Roff Smith. “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.”
The Menga dolmen is a roughly 82-foot-long chamber covered with an earthen mound, and its roof, walls and columns are composed of 32 large stone slabs. The stones’ combined weight is approximately 1,140 tons—heavier than two Boeing 747 airplanes loaded with passengers, reports CNN’s Katie Hunt. While the chamber’s purpose is unknown, scientists suggest it served a funerary function.
“Initially, what most sparked my interest in the Menga dolmen was its monumentality,” José Antonio Lozano Rodríguez, a geologist at the Spanish Institute of Oceanography and first author of the research, tells Interesting Engineering’s Mrigakshi Dixit. “Entering its interior and contemplating such a colossal monument from the Neolithic period aroused my curiosity to learn more about this dolmen.”
The research team conducted a geoarchaeological analysis of the site by examining laser scans and visuals from earlier excavations, ethnographic descriptions of building techniques, and the area’s topography. With this data, researchers inferred the Neolithic engineers’ construction process.
A previous study by the same team had already established that the stones were sourced from 0.6 miles away, at a quarry that sits at a strategically higher elevation than the Menga dolmen. The builders would have most likely transported the stones using sleds on a track made from wooden beams, which implies a knowledge of friction, acceleration and center of mass.
Once at the site, the stones making up the walls and columns were placed upright into deep cavities so that up to one-third of each stone was underground, per CNN. Builders probably achieved this using counterweights and ramps that had to take into consideration the relatively soft—and thus easily damaged—nature of the sandstone rock. The wall stones were carved to interlock with and lean against each other, adding to the stability of the structure.
“These people had no blueprints to work with, nor, as far as we know, any previous experience at building something like this,” study co-author Leonardo García Sanjuán, an archaeologist at the University of Sevilla in Spain, tells Nature News. “There’s no way you could do that without at least a basic working knowledge of science.”
The walls tilt slightly inward—standing at angles between around 84 and 85 degrees—so that the top of the chamber is narrower than the bottom in a trapezoidal shape. The largest of the five capstones was carved to increase stress distribution—essentially creating a rudimentary arch—with its center higher than its sides.
“To the best of our knowledge, this is the first time that the principle of the arch has been documented in human history,” García Sanjuán tells New Scientist’s Tom Leslie.
Assembling the chamber with its walls partially underground also meant that the capstones could be placed on top without having to be lifted very high. Builders then dug out the ground inside to lower the chamber’s floor level, while the outside was covered in soil to insulate and further stabilize the construction.
“We have to call it science,” García Sanjuán tells CNN. “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,” 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.”
