The Ring of Brodgar, sometimes called the Ring of Brogar, is a stone circle superbly located on land rising above the saltwater Loch of Stenness and the freshwater Loch of Harray. When first erected there were 60 stones here, in a perfect circle 104m in diameter. Today just 36 of the original stones are still standing, and one of those only just, having been split vertically by a bolt of lightning on 5 June 1980.
The ring of stones is surrounded by a ditch cut into the rock that was 6m wide and 3m deep. There are entrance causeways across the ditch on the north-west side and on the south east-side.
It is thought that the Ring of Brodgar was built between 2500BC and 2000BC. To put this in context, the earliest of these dates is about 600 years after Skara Brae was first occupied several miles to the west, about 300 years after Maeshowe was built, within sight to the south east, and probably some time after the Stones of Stenness had already been erected also within sight to the south.
Constructing the circle would have been a mammoth task. It has been estimated that it would have taken 10,000 man-days to dig the ditch alone, plus several thousand more man-days to find, transport and erect the stones.
Several hundred people could therefore have built the circle in one summer if they had done nothing else, or fewer people might have built it over a longer period of time.
Why would a society living on limited resources have spent so much effort building the Ring of Brodgar? Was it a lunar observatory? Was it used for some unspecified ceremony? Whatever the answer, and no-one really knows, it is certain it must have meant a great deal to the people who built it. In recent years excavations at the nearby Ness of Brodgar have unearthed what some have called "Britain's Ancient Capital", and it seems clear that the Ring of Brodgar formed part of the same ancient landscape.