The Lines were first spotted when commercial airlines began flying across the Peruvian desert in the 1920s. Passengers reported seeing ‘primitive landing strips’ on the ground below. The Lines were made by removing the iron-oxide coated pebbles which cover the surface of the desert. When the gravel is removed, they contrast with the light color underneath. In this way the lines were drawn as furrows of a lighter color. On the Pampa, south of the Nasca Lines, archaeologists have now uncovered the lost city of the line-builders, Cahuachi. It was built nearly 2,000 years ago and mysteriously abandoned 500 years later.
Toribio Megia Xespe, a Peruvian doctor and anthropologist was the first scientist, in 1927, to show interest in what he called "great Incan ceremonial artifacts".
Swiss writer Erich von Däniken suggested in his 1968 book, "Chariots of the Gods", that the lines were built by ancient astronauts as a landing field. But the soft clay soil and layer of brown and black rocks in the Nazca desert would seem an unsuitable site for a landing strip.
Residents of the local villages say the ancient Indians conducted rituals on these giant drawings to thank the gods, and to ensure that water would continue to flow from the Andes.
Parts of this article are from the NASA Earth Observatory; [1]