Geoglyphs, petroglyphs, petrographs: These three terms are used to describe artworks done by prehistoric societies. Although they may be used interchangeably, distinctions do exist.

Geoglyphs are gigantic drawings made on the sides of hills. Only in three parts of the Americas were these made: Arizona (US), Nasca (Peru) and Northern Chile from Arica to Iquique. Techniques varied, but principally consisted of the earth being scraped with the design. In some environments, like Nasca, the morning dew was sufficient to hold the form of the design intact for centuries. In other instances, like the Atacama Desert, urine was used. Rocks may be added to outline the figure for heightened distinction.

Petroglyphs are rock (petro) carvings (glyphs), or stones engraved with geometric, anthropomorphic and animal pictures. Petrographs, also called pictographs, are paintings done on rocks, usually inside caves or in protected recesses. Both these techniques are common throughout the Americas and other parts of the world.