There's an extraordinary world of speculation surrounding the construction of Stonehenge, and precisely how the stones–which average 25 tonnes a piece–made it 140 miles from Wales to Wiltshire, England in a construction process that took a whopping 1,500 years. Depending on ones proclivity, the 5,000 year-old icon was constructed by a giant, by aliens, or by a very large number of very exhausted workers who did the whole thing manually.
The last theory is certainly the most plausible, and one team of archeologists from University College, London recently undertook to determine just how many people would be required to move the massive rhyolite bluestones to their current location. In an intensely practical experiment, they grabbed a one tonne stone (the same weight as the smallest at Stonehenge), some logs, some ropes, and some volunteers.
The rig to carry out the back-breaking work included a sycamore sledge designed to closely match those found throughout the ancient world. As team leader Barney Harris, a researcher at UCL, explained to The Telegraph:
We know that pre-industrialised societies like the Maram Naga in India still use this kind of sledge to construct huge stone monuments. And similar y-shaped sleighs have been found dating back to 2000BC in Japan which we know were used to move megaliths.
Harris had estimated that it would take 15 people to drag the one tonne boulder, and 50 to drag it into position. But in the course of the experiment, Harris found that it was–relatively speaking–much easier than he had anticipated. Just 10 people were able to move the boulder along the rig, moving it at a speed of 10 feet every five seconds, which works out to one-mile-per-hour. Not too shabby.
And while the experiment took place on the flat grounds of Gordon Square, London, Harris believes that the rig would've had no problem navigating the rugged terrain of the Preseli Mountains in Wales. Further more, he believes his experiment debunks theories that ancient construction projects utilized oxen to drag monstrously heavy building materials.
[A]ctually oxen are quite belligerent and difficult to control. This experiment shows that humans could have carried out the task fairly easily.
With his newly acquired data, Harris now plans to go back and calculate exactly how long it would've taken to move each boulder along the 140-mile route, and after that, determine precisely how the rocks were moved into place.