Jarlshof is the best known prehistoric archaeological site in Shetland, Scotland. - Described as "one of the most Remarkable Archaeological Sites ever excavated in the British Isles", it contains Remains dating from 2500 BC up to the century AD.
This petroglyph from Siberia is dated to around 5000 BCE. (It reminds me of legends of many-headed demons from the Ramayana, though Ravana had ten heads. And also of Tilak's theory of an Arctic source for the Vedas).