The reasons behind the geoglyphs are still unknown, despite a number of compelling theories.  In the arid coastal plains of southern Peru lies a mystery that has baffled scientists and archaeologists for almost a century. Etched out of the sand by ancient indigenous people for reasons which are still largely unknown, the purpose of the Nazca Lines has spawned countless theories since their discovery some 80 years ago.  Harry Stewart lays out the story behind Peru's mysterious Nazca Lines in this interesting article published  on The Omnivore.