From the Nazca region of Peru They are geoglyphs or "drawings" on the ground, created by the removal of rocks and earth to create a "negative" image. Predating the Inca Empire, their origin is unknown. The most common theories, however, indicate they were used in ritual & believers of extraterrestrials claim they are evidence of ancient alien activity. Ranging in size from 30-180 meters, Nazca Lines are too large to be seen from the ground. Visible from an elevated view of 20+ feet, many of them depict certain plants animals or geometric figures. Locals from the Nazca Plateau region of Peru etch the most common patterns onto river rock from that area, creating the Nazca Line Stones.