Geoglyphs

Geoglyphs are large-scale designs or motifs produced on the ground by removing surface material to reveal a different underlying layer, or by adding material to the surface. They are usually made on desert or prairie terrain where soil color contrasts are pronounced. Geoglyphs range from simple geometric shapes to intricate representations of animals, plants, or symbols. They are best observed from the air or from surrounding elevations.

They occur worldwide, with some of the best-known examples in Peru, England, and Chile. The Nazca Lines and nearby Palpa Lines in southern Peru date from roughly 500 BCE to 500 CE and consist of hundreds of figures spanning tens of meters to hundreds of meters in length. Other well-known geoglyphs include the Uffington White Horse and the Cerne Abbas Giant in England, and the Atacama Giant in Chile.

The purposes of geoglyphs remain debated. Theories include ritual or ceremonial use, astronomical alignments, territorial markers, or commemoration of events or groups. Their construction would have required extensive planning, seasonal labor, and coordination across communities. Geoglyphs are difficult to date precisely, often inferred from stylistic analysis, pottery associations, and overlap with known cultures.

Today geoglyphs are valued for their cultural and archaeological significance and are protected in several sites by national authorities and international organizations. They face threats from agricultural development, construction, and erosion. Researchers use aerial photography, satellite imagery, and GIS to document and monitor these landscapes.