The Nazca lines are monumental geo-glyphs carved lightly into the earth in southern Peru, and were made by the Nazca culture between around 400 and 600 C.E. The lines form symbolic shapes, including animals, and natural and geometric forms, such as a hummingbird, monkey, lizard, a flower, tree, and a spiral and trapezoid. These shapes, some of which are over four hundred feet long, were made by removing a top layer of red-pebbled earth to reveal a whiter surface underneath. Scholars wonder if the Nazca geoglyphs were depictions of constellations, or in some way linked to astronomy, but no conclusive connection has been found. It is possible the Nazca lines were an important part of religious ritual, or were intended for a divine audience, as they are best seen from the air.