In 2007, a massive prehistoric wall was unearthed on the Ness.
The discovery of the four-metre thick wall, together with geophysics scans showing a distinct lack of human activity around the Ring of Brodgar, suggested that the wall had some symbolic, or ritualistic, function.
The cut-off point between activity and no activity seems to have been differentiated by the huge wall, which prompted the theory that it may have separated the Neolithic realms of the living from that of the dead.
In 2008, a trench was opened to see whether the wall extended right across the Ness — which it certainly appears to do — forming a clear barrier between the south-eastern and north-western sections.
A trench opened at the start of the 2008 excavation hinted that a massive ditch had been dug directly outside the wall.
Further examination, however, revealed that a second two-metre wide section of wall had been built adjacent to the first, along with a ditch running parallel to the wall.
It is suspected that the second wall section was added late in the history of the site, perhaps after the original wall had collapsed, or was dismantled.
The addition of this second section, it’s been suggested, could have been a later attempt to monumentalise the original construction, or enhance an entrance through the wall.
An exploratory trench over the wall revealed what could be more buildings, and a possible hearth, which would imply that the wall fell out of use, towards the very end of the Neolithic and maybe into the Bronze Age, and structures spilled out to the north-west.
In 2017, It also became clear that the “Great Wall” not only curved to follow a path along the shore of the Harray Loch, but curled closely around Structure Five — suggesting that it, too, was a very early element in the history of the site.
This was confirmed by excavation, which showed nothing lay beneath the wall section except the natural boulder clay on which it was built.