Blackhammer Tomb, within Frotoft, Rousay was a burial place for a farming community in this area of Rousay, over 4,500 years ago.
The tomb measures 13 metres in length.
The cairn was excavated in 1936, when the remains of two men were found inside.
A broken Unstan Ware bowl was also found, along with flint and bone tools.
Over the years, the cairn has become badly damaged, although a modern roof and entrance were later added to protect the remains, which are only a few feet high. The new roof contains windows, providing the light needed to fully appreciate the hard work which went into creating this site. The modern entrance provides access by a ladder and a hatchway in the roof. The original entrance was sealed up when the cairn was abandoned.