Since their startling discovery in Peru’s coastal area during the 1920s, mystery still surrounds the so-called Nazca lines, depicting several massive images decipherable only from high altitudes.
The vast majority of the lines date from 200 BC to 500 AD, to a time when a people referred to as the Nazca inhabited the region. The earliest lines, created with piled up stones, date as far back as 500 BC.
According to LiveScience.com:
The purpose of the lines continues to elude researchers and remains a matter of conjecture. Ancient Nazca culture was prehistoric, which means they left no written records.
One idea is that they are linked to the heavens with some of the lines representing constellations in the night sky. Another idea is that the lines play a role in pilgrimage, with one walking across them to reach a sacred place such as Cahuachi and its adobe pyramids.
Yet another idea is that the lines are connected with water, something vital to life yet hard to get in the desert, and may have played a part in water-based rituals.
In the absence of a firm archaeological conclusion a number of fringe theories have popped up, especially several aligned with “ancient astronaut” theories. A less radical suggestion is that the Nazca people used balloons to observe the lines from high altitudes, something for which there still is no archaeological evidence.