Buckhorn Wash Rock Art Panel, Barrier Canyon Style, dating from 2000 BC to 1 AD, San Rafael Swell, Utah, United States of America, North America

Buckhorn Wash Rock Art Panel, Barrier Canyon Style, dating from 2000 BC to 1 AD, San Rafael Swell, Utah, United States of America, North America

Buckhorn Wash Rock Art Panel, Barrier Canyon Style, dating from 2000 BC to 1 AD, San Rafael Swell, Utah, United States of America, North America

Buckhorn Wash Pictograph Panel, with snake symbol and human, Barrier Canyon Style, dating from 2000 BC to 1 AD, San Rafael Swell, Utah, United States of America, North America

Buckhorn Wash Rock Art Panel, Barrier Canyon Style, dating from 2000 BC to 1 AD, San Rafael Swell, Utah, United States of America, North America

Buckhorn Wash Rock Art Panel, Barrier Canyon Style, dating from 2000 BC to 1 AD, San Rafael Swell, Utah, United States of America, North America

Ring of Brodgar, stone circle dating from between 2500 and 2000 BC, 27 out of 60 stones still standing, UNESCO World Heritage Site, Mainland, Orkney islands, Scotland, United Kingdom, Europe

Ring of Brodgar stone circle dating from between 2500 and 2000 BC, 27 stones of 60 still standing, UNESCO World Heritage Site, Mainland, Orkney Islands, Scotland, United Kingdom, Europe

Chambered cairn dating from 2000 BC at Cairnholy near Creetown, Dumfries and Galloway, Scotland, United Kingdom, Europe

Loanhead of Daviot stone circle dating from between 2500 and 2000 BC, Daviot, Aberdeenshire, Scotland, United Kingdom, Europe

A chambered cairn, the smaller one of two, dating from 2000 BC, near Creetown, Dumfries and Galloway, Scotland, United Kingdom, Europe

Monoliths prepared in gneiss Lewis, erected about 2000 years BC.