Ring of Brodgar

The Ring of Brodgar is part of the Neolithic World Heritage site on Orkney. This ring of stones once included 60 stones, 36 still survive. They are thought to have been created in the 3rd millennium BC, about 5000 years ago!
The nearby Standing Stones of Stenness are also worth a visit.
Both are now managed by Historic Environment Scotland.

The Ring of Brodgar, also known as the Ring of Brogar, located on Mainland (Orkney), belongs, together with the Ness of Brodgar, Skara Brae, the Stones of Stenness and Maeshowe, to the Neolithic Heart of Orkney, which has been designated by UNESCO since 1999. the World Heritage List has been added.
The ceremonial ring and stone circle is dated to between 2500 and 2000 BC and is located on a narrow isthmus between the Loch of Stenness and the Loch of Harray. Of the original sixty stones, only 36 remain. The stones are not decorated, except for five Norse runes and a cross. The runes form a cryptogram with the common name Bjorn. There is a moat around the circle, which must have been 3 meters deep originally.
(Wikipedia)

Two Neolithic standing stones sites within metres of each other! Also a lovely ride along this road