It was once thought that art and symbolic culture first emerged in Europe some 40,000 years ago, during the Middle-to-Upper Palaeolithic transition – often termed the 'symbolic explosion' or 'Upper Palaeolithic revolution'. Some archaeologists still adhere to this view. Others now accept that symbolic culture probably emerged in sub-Saharan Africa at a much earlier date, during the period known as the Middle Stone Age.[10] The evidence consists of traditions of ground ochre with strong selection for the colour red, examples of so-called ochre 'crayons' which appear to have been used for purposes of design, probably on the body, and geometric engravings on blocks of ochre.