Geoglyphs are works of art that are made either by making mounds out of material like rocks or soil or by digging lines or shapes into the soil. Most geoglyphs are impossible to see as art at ground level. They simply look like grooves or mounds in the earth. You may not even see them at all. However, if you see them from a plane, what they are becomes clear.

Some examples of geoglyphs are the Nazca lines in Peru and the Serpent Mound in Ohio, U.S.A. These…