Moving very large stones
Stonehenge is often portrayed as if it were a unique monument, which in some respects it is. No other surviving monument uses mortise-and-tenon joints to lock the lintels to the uprights that form the massive stone circle and the inner trilithons (though this kind of joint was probably used in similar monuments built from timber that have not survived). But the use of colossal stones is far from unique, and there are numerous examples around the world that demonstrate the astonishing skill with which our prehistoric ancestors were able to quarry, transport, and erect massive stone monuments.
One of the earliest of these – the Dolmen de Menga, located near Antequera, Málaga, Spain – is the subject of an article in Science Advances (https://doi.org/10.1126/sciadv.adp1295) in which the authors explain how this huge stone construction was built. The Menga dolmen is one of the oldest of the great megalithic structures in Europe (dating to between 3800 and 3600 BC). Built with 32 sandstone slabs, the interior measures 27.5m in length, 6m in width, and 3.5m in height. The principal capstone weighs c.150 tons, making it the largest megalithic stone ever moved in Iberia, and the combined weight of the monument has been estimated at 1,140 tons or, as CNN reporter Katie Hunt put it, ‘heavier than two Boeing 747 airplanes loaded with passengers’.
The stones were sourced from 850m away, at a quarry that sits at a higher elevation than the dolmen, and the builders probably moved them on sledges, riding on wooden track. The bottom third of each upright occupies a deep pit dug into the underlying bedrock. The stability of the outer wall was achieved by leaning the stones inward at an angle of c.85°, so that the top of the chamber is narrower than the base. The edges of the orthostats were shaped so that all the stones interlocked and supported each other.
