Juergen Freund / Ancient pictographs (rock / cave paintings) of fish and sea creatures on karst limestone formations. Sunmalelen area, Raja Ampat, West Papua, Indonesia, January 2010

Donald M. Jones / Desert Bighorn Sheep (Ovis canadensis nelsoni) pictograph, Valley of Fire, Nevada

Dong Lei / Man pointing at Naxi pictograph character written on blackboard, Yunnan, China

Dong Lei / Naxi / Dongba pictograph characters, Lijiang Laojunshan National Park, Yunnan, China, July.

Michael Durham / Greater Kudu (Tragelaphus strepsiceros) depicted in San Bushman rock paintings, estimated at around 2000 years old, Nswatugi Cave, Matobo National Park, Zimbabwe

Michael Durham / Southern Giraffe (Giraffa giraffa) and other wildlife depicted in San bushman rock paintings, estimated at around 2000 years old, Nswatugi Cave, Matobo National Park, Zimbabwe

Vincent Grafhorst / Bushman rock paintings in the Drakensberg Mountains, Giant's Castle Nature Reserve, South Africa

Vincent Grafhorst / Bushman rock paintings in the Drakensberg Mountains, Giant's Castle Nature Reserve, South Africa

Jim Brandenburg / Pictographs, Lac La Croix, Boundary Waters Canoe Area Wilderness, Minnesota

Matthias Breiter / Aboriginal rock paintings at Nganalam Art Site, Keep River National Park, Australia

Richard Du Toit / Bushman rock art, fallen rock site, Bushman Kloof, Cederberg, South Africa

Jeff Foott / Pictographs, Hundred Hands Panel, Grand Staircase-Escalante National Monument, Utah