The Cuween Hill cairn is built, unsurprisingly, into Cuween Hill, by the village of Finstown, in the Mainland parish of Firth.
The structure at the end of a trail that climbs up the east-facing slope of the hill.
Although small by Maeshowe's standards, the Cuween cairn is nonetheless an impressive feat of prehistoric engineering.
Cut into solid bedrock, the cairn comprises a main central chamber with four smaller chambers branching off from each wall.
Access to the interior is by a low, narrow, entrance passage, which, being less than one metre high, requires the visitor to get down on their hands and knees and crawl.
Once inside, however, the main chamber is fairly spacious and the visitor can stand comfortably - although in pitch black darkness.
Today, the chamber is over two metres high, but the original roof - which was damaged by 19th century "explorers" breaking into the cairn from above - was probably higher.
Thought to date from around 3,000 BC, the cairn was excavated in 1901.
Back then, the remains - mostly skulls - of at least eight people were found inside. This small number led to the suggestion that, during its use, the chamber was cleared out periodically, with only the most recent, or significant, skulls left within.
The dog skulls
Aside from the human bones, perhaps the most interesting discovery was that of 24 dog skulls. This led to the suggestion that the tomb’s users may have had totem animals.
However, over the years the relevance of these dog skulls has been queried, with suggestions that they may post-date the period the cairn was in use.
But recent radiocarbon dating of a fragment of bone, by the National Museums of Scotland, has confirmed the dog skulls and the tomb are contemporary.
So, just as the sea eagle was significant to the later users of the Isbister cairn in South Ronaldsay, perhaps the creators of the Cuween cairn venerated the dog, or held it as their tribal symbol?
One theory has it that dogs may have been used to strip the flesh from the dead before their remains were interred in the tomb.
Or perhaps the dog was seen as a guardian, watching over the house of the dead, just as they did with the nearby houses of the living.
Whatever the reason, all we can really say with any degree of certainty is that the dog was in some way significant to the people using the cairn.
To the north-east of the cairn, on the side of Wideford Hill, is the Wideford cairn, while the site of the Stonehall settlement is in the valley directly below Cuween Hill.
Stonehall was an extensive Neolithic village that predates the Knap o' Howar in Papay.
Given the close proximity of the Cuween cairn to the Stonehall settlement, and the fact that the two were contemporary, would indicate that those who lived in the settlement were also responsible for the construction and use of the cairn.