Dating from c.3100 – 2200BC, the best preserved sequence of Neolithic building developments is at Skara Brae, Orkney.
Skara Brae. Interesting view...looks as if part of the island was snapped off 'yesterday'
The largest and most extensive group of prehistoric cup-and-ring marked rock carvings in Scotland exists at Achnabreck in Argyll. Whist a variety of enigmatic concentric circles, alignments and other features are cut into three exposed rock outcrops the examples are representative of the first true form of stone art to be found in Scotland. Although no full understanding of what the purpose of this art form was, similarities can be identified in the overall form and plan shape of Broch sites some millennia later.
Orkney Petroglyph...something astronomical? (Saturn Myth, methinks.)