There has never been an explanation for the vast lines, and artwork, created sometime between 200 and 600 B.C. There are miles and miles of geometric shapes etched into the landscape that will most likely baffle us for all of time.
When the best views are from the air, it is quite unbelievable that these were not made by extraterrestrials. A link to astronomy, messages of some kind?
In some ways, on a smaller scale, do the modern day crop circles tell a similar story?
http://www.crystalinks.com/nazca.htmlTim