Steven Kazlowski / Petroglyphs on Newspaper Rock, a boulder in Canyonlands National Park, Utah, USA. 2009.

Angelo Gandolfi / Prehistoric rock painting of Reindeer in Tito Bustillo cave, Asturias, Spain. July 2008.

Angelo Gandolfi / Prehistoric rock painting of a fox (Vulpes vulpes), Albxerri cave, Pais Vasco, Spain. July 2008.

Wild Wonders of Europe / Krahmer / Rock piles with the Paternkofel and Tre Cime di Lavaredo mountains, Sexten Dolomites, South Tyrol, Italy, Europe, July 2009

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

Tim Laman / Aboriginal rock art with many human hands, at a site called "The Art Gallery", Carnarvon Gorge, Carnarvon National Park, Queensland, Australia

Steven David Miller / A rock art shelter in the northern Kimberley region features a cluster of Wandjina figures peering out from the sandstone rock surface, Northern Kimberley region and the Mitchell Plateau, Western Aust...

Steven David Miller / Bradshaw rock art / Gwion Gwion, Northern Kimberley region and the Mitchell Plateau, Western Australia

Bernard Castelein / Prehistoric rock painting of men and beast, Bhimlat Rajasthan, India

Jouan & Rius / Aboriginal rock art, Anbangbang Gallery, Nourlangie Ranges, Kakadu National Park, Northern Territory, Australia

Jouan & Rius / Aboriginal rock art showing sailing boat, Nanguluwur Gallery, Nourlangie Ranges, Kakadu National Park, Northern Territory, Australia

Jouan & Rius / Aboriginal rock painting, Art Gallery Cave, Carnarvon National Park, Queensland, Australia. The painting is believed to me more than 2000 years old and shows hands, boomerangs, emu feet and rock walla...