Surviving Cro-Magnon artifacts include huts, cave paintings, carvings and antler-tipped spears. The remains of tools suggest that they knew how to make woven clothing. They had huts, constructed of rocks, clay, bones, branches, and animal hide/fur. These early humans used manganese and iron oxides to paint pictures and may have created the first calendar around 15,000 years ago. The flint tools found in association with the remains at Cro-Magnon have associations with the Aurignacian culture that Lartet had identified a few years before he found the skeletons. The Cro-Magnons must have come into contact with the Neanderthals, and are often credited with causing the latter's extinction, although morphologically modern humans seem to have coexisted with Neanderthals for some 60,000 years in the Levant and for more than 1000 years in France.
The most common themes in cave paintings are large wild animals, such as bison, horses, aurochs, and deer, and tracings of human hands as well as abstract patterns, called Macaroni by Breuil. Drawings of humans are rare and are usually schematic rather than the more naturalistic animal subjects. Cave art may have begun in the Aurignacian period (Hohle Fels, Germany), but reached its apogee in the late Magdalenian (Lascaux, France).
The paintings were drawn with red and yellow ochre, hematite, manganese oxide and charcoal. Sometimes the silhouette of the animal was incised in the rock first. Stone lamps provided some light. Abbé Breuil interpreted the paintings as being hunting magic, meant to increase the number of animals. As there are some clay sculptures that seem to have been the targets of spears, this may partly be true, but does not explain the pictures of beasts of prey such as the lion or the bear.
An alternative and more modern theory, based on studies of more modern hunter-gatherer societies, is that the paintings were made by Cro-Magnon shaman. The shaman would retreat into the darkness of the caves, enter into a trance state and then paint images of their visions, perhaps with some notion of drawing power out of the cave walls themselves. This goes some way towards explaining the remoteness of some of the paintings (which often occur in deep or small caves) and the variety of subject matter (from prey animals to predators and human hand-prints). However, as with all prehistory, it is impossible to be certain due to the relative lack of material evidence and the many pitfalls associated with trying to understand the prehistoric mindset with a modern mind.
The oldest petroglyphs are dated to approximately 10,000 to 12,000 years ago. Around 7,000 to 9,000 years ago, other writing systems such as pictographs and ideograms began to appear. Petroglyphs were still common though, and tribal societies continued using them much longer, even until contact with Western culture was made in the 20th century. These images probably had deep cultural and religious significance for the societies that created them; in many cases this significance remains for their descendants.
Some researchers have noticed the resemblance of different styles of petroglyphs across different continents; while it is expected that all people would be inspired by their surroundings, it is hard to explain the common styles. Explanations for this similarity are mostly grounded in Jungian psychology and the views of Mircea Eliade. According to these theories it is possible that the similarity of petroglyphs (and other atavistic or archetypal symbols) from different cultures and continents is a result of the genetically inherited structure of the human brain. Other theories suggest that petroglyphs were made by shamans in an altered state of consciousness, perhaps induced by the use of natural hallucinogens.
Many of the geometric patterns (known as form constants) which recur in petroglyphs and cave paintings have been shown to be "hard-wired" into the human brain; they frequently occur in visual disturbances and hallucinations brought on by drugs, migraine and other stimuli.
The Nazca Lines are gigantic geoglyphs located in the Nazca Desert, a high arid plateau that stretches 53 miles between the towns of Nazca and Palpa on the Pampas de Jumana in Peru. They were created by the Nazca culture between 200 BC and 600 AD. There are hundreds of individual figures, ranging in complexity from simple lines to stylized hummingbirds, spiders, monkeys, and lizards. The Nazca lines cannot be recognized as coherent figures except from the air. Since it is presumed the Nazca people could never have seen their work from this vantage point, there has been much speculation on the builders' abilities and motivations. Since their discovery, various theories have been proposed regarding the methods and motivations behind the lines' construction. The accepted archaeological theory is that the Nazca people made the lines using nothing but simple tools and surveying equipment. Wooden stakes in the ground at the end of some lines (which, coincidently, were used to date the figures) support this theory. Furthermore, Joe Nickell of the University of Kentucky has reproduced one of the figures using the technology available to the Nazca Indians of the time without aerial supervision. With careful planning and simple technologies, a small team of individuals could recreate even the largest figures within a 48 hour period. However, there is not much extant evidence concerning 'why' the figures were built, so the Nazca's motivation remains the lines' most persistent mystery. Most believe that their motivation was religious, making images that only gods could see clearly. The details of their theology, however, remain unsolved.