The Nazca Lines are large animal and abstract geoglyphs made from rocks in a desert in northern Peru. Created by people of the Nasca culture, the Nasca Lines were made between AD 400 and 650. Essentially, the lines were made by moving or turning desert-varnished rocks so that their lighter underside is visible.
The researcher most associated with the Nazca Lines is, of course, Maria Reiche, although Erich Von Daniken with his wacky ideas about alien landing zones comes a close second. Archaeoastronomer Anthony Aveni explored the possible meanings and uses of the lines in his 2000 book called Between the Lines. Aveni feels that possible interpretations of the lines includes a solar or lunar calendar, art or religious significance, or roadways; probably all three.
Sources
This glossary entry is part of the About.com Guide to the Nazca Civilization and the Dictionary of Archaeology.
Isbell, William H. 1978 The prehistoric ground drawings of Peru. Scientific American October 1978: 69-76.
Rink, W. J. and J. Bartoll 2005 Dating the geometric Nasca lines in the Peruvian desert. Antiquity 79(304):390-401.
Silverman, Helaine and David Browne 1991 New evidence for the date of the Nazca lines. Antiquity 65:208-220


