Paul D Stewart / Illustration of trilobuite (Paradoxides bohemicus), Plate 1. From 'Organization of the Trilobites' by Hermann Burmeister, appearing in the Ray Society translation of his work published in 1846. The Il...

Konrad Wothe / Prehistoric Rock Art, Awis Valley, Akakus mountains, Libya, Sahara, North Africa, November 2007

Konrad Wothe / Stone engravings of Giraffes in Wadi Mathendous, Wadi Barjuj, Stony Desert, Libya, Sahara, North Africa, November 2007

Rob Tilley / Rock engravings of the native american Pueblo people, Chaco Culture National Historical Park, New Mexico, USA, February 2009

Jouan & Rius / Bushman rock engravings of animals, Twyfelfontein, Damaraland, Namibia,

Jouan & Rius / Bushman rock engravings of animals, Twyfelfontein, Damaraland, Namibia,

Jack Dykinga / Signal Hill petroglyphs at sunset with Saguaro Cacti (Carnegiea gigantea) and Tucson Mountains in the background, Saguaro National Monument, Arizona, USA

Steven David Miller / Stencilled handprint rock art. Baloon Cave, Carnarvon Gorge, Carnarvon National Park, Queensland. 2014.

Steven David Miller / Rock art with stencilled hands, boomerangs and animal footprints . The Art Gallery, 62m of rock with 2000 stencils, engravings and paintings. Baloon Cave, Carnarvon Gorge, Carnarvon National Park, Que...

Steven David Miller / Stencilled tool rock art in The Art Gallery, 62m of rock with 2000 stencils, engravings and paintings. Baloon Cave, Carnarvon Gorge, Carnarvon National Park, Queensland. 2014.

Steven David Miller / Handprint rock art created through spitting ochre over hands. In The Art Gallery, 62m of rock with 2000 stencils, engravings and paintings. Baloon Cave, Carnarvon Gorge, Carnarvon National Park, Queen...

Steven David Miller / Rock art with stencilled hands and boomerang. The Art Gallery, 62m of rock with 2000 stencils, engravings and paintings. Baloon Cave, Carnarvon Gorge, Carnarvon National Park, Queensland. 2014.