Background
The Nazca (or Nasca) desert is in Peru. It runs along the Pacific Ocean for close to 1400 miles (about 2253 km). It is part of a high plateau; the part with the lines is called the Pampa Colorada ("Colored Plain" or "Red Plain"). They take up an area about 190 square miles (500 square km), the name coming from the dark red ("rust") of the rocky surface and soil (though a desert, there is no sand, only rocks, pebbles, and soil).
The Nazca Indians lived in the area between 300 BC to 800 AD (thought to be a predecessor of the Inca). They left no trace of written language. It is known that they were agricultural and had developed successful irrigation systems that allowed them to live in the bleak, nearly rainless area. The crops were irrigated through channels and tunnels in a subterranean system. They had access to this system and were able to control irrigation. This supports the idea that they were sophisticated in engineering problems (important later). The soil of the area, while terribly dry, is fertile and all that was needed was the transportation of water.
They did leave a good deal of art/artifacts behind. They wove garments and made pottery. Of note is that the animal designs often found on the work is highly similar to those of the "lines" in question.
The Nazca either died out or were assimilated into other groups. No known descendants survive today.
The lines
The lines/"drawings" come in two different forms: geoglyphs and biomorphs. Geoglyphs (while a general term for all the lines) are straight lines and geometric patterns, including triangles, trapezoids, zigzags, circles, and spirals (nearly 300 of them). Biomorphs are the ones that represent living creatures: "a spider, a monkey, a whale, a snake, a lizard, a flower, a man, and 18 bird shapes, including the hummingbird and the condor;" plants as well. There are around seventy of these, ranging from 82 to 935 feet (25m to 285m long)—some of the straight lines even longer.
The lines are very difficult to see while on the ground without already knowing of their existence and where they are located. They weren't officially discovered (first recorded by a Peruvian archaeologist in 1926) until planes could be flown over the area.
The lines present two main questions to those interested: how they were made and why they were made.
Nazca lines: a "How to" guide
While there are some fringe theories as to how the lines were made and "so precise" over long distances, for outlines really only visible from the air, the "how" is a relatively easy question (the "theories" will be addressed momentarily). As noted, the Nazcas already had acquired knowledge of engineering and building ideas through their development of the all-important irrigation systems (in fact many believe the lines intimately connected to water for one reason or another). And it is a task that, although requiring a lot of effort and time, is managed without surveying equipment or even rulers.
The way the lines "show" is because under the darkened rocks and upper soil, is a soil of a much lighter color—this is what diffentiates the lines from the landscape. The physical job is to move aside the upper, darker stuff to reveal the yellowish soil beneath. Again, much effort and time would be necessary to do that sort of work, but hardly something requiring industrial age "technology," let alone anything today (or alien—and you know the aliens are coming—be patient).
As for the lines,
two wooden stakes could be used to guide the placement of a third stake along the line. One person "sights along" the first two stakes and instructs a second person where to place the third stake. Strings could also have been used to help ensure the lines were straight. This process could be repeated for hundreds of kilometres with due diligence.
The non-straight lines could have been created using a grid system—not so far-fetched, as they used a similar thing (albeit on a much smaller scale) in weaving patterns and designs.
In 1984, volunteers helped a scientist attempt to replicate the process the Nazcas most likely used. They were able to construct a straight line that turned into a spiral about 115 feet long (35m) and 3.2 feet wide (1m). Without a printed plan, it took the group of ten only an hour and a half and the result was as "accurate" as any of the Nazca lines.
According to the conclusions drawn from the experiment (by extrapolation), it would have taken about a week for the team to complete an average-sized trapezoidal figure (area 16,000 square meters or over four acres). Further, a work force of around 10,000 people could probably complete all of the figures in about a decade. Again, time and effort? Yes. Technologically difficult? No. Consider the ease and simple tools used by the Crop Circle Hoaxers to create complex geometric patterns.
A little aside. It seems common that accomplishments of this nature are sometimes dismissed by those on the fringe, evoking "lost tribes" from Atlantis or extraterrestrial architects (or "magic"—dropping the pretentious and superfluous "k" from the end). It is interesting that with the exception of Stonehenge, these claims are almost entirely for creations of dark-skinned people—the pyramids of Egypt and Central America, the remarkable Inca cities of Cuzco and Machu Picchu, the Nazca lines (of course), and the statues on Easter Island. I wonder if that doesn't say more about those making the claims than about the people whose "blood, toil, tears, and sweat" went into making those things.
Why are they still there?
As the line goes: "location, location, location." The climate and place in the world make all the difference:
Stones (not sand) comprise the desert surface. Rusted by humidity, their darkened color increase heat absorption. The resulting cushion of warm surface air acts as a buffer against the wind; while minerals in the soil help to solidify the stones. On the "desert pavement" thus created in this dry rainless environment, erosion is practically nil—making for remarkable preservation of the markings (qtd. at skepdic.com)
While they are well preserved and will remain so, climate willing, damage has been done from vehicle traffic in the area. UNESCO added it to the World Heritage List in 1994.
But, WHY?
Since question #1 has been taken care of, we come to question #2, which is not so easily explained.
"The stars..."
One of the earliest investigators of the lines was an American geographer name Paul Kosok. Though he first considered they were related to the irrigation system, he changed his mind. While studying the work of the Nazca, he had noticed that the sun seemed to set at the end of one of the long lines on 22 June (winter solstice south of the equator). This led to his conclusion that the lines were "the largest astronomy book in the world." Years later, a mathematician (Maria Reiche) took that hypothesis and speculated on it. Spending years mapping out and measuring the lines, she came to the same conclusion and expanded on it, believing the calculations based on the lines predicted the positions of the sun, moon, planets, and stars and that they were used as a sort of almanac-calendar, used to determine when to plant and harvest.
This hypothesis was challenged in the 1960s when an astronomer (Gerald Hawkins) fed the lines and astronomical positions into a computer and found they were no more "accurate" (as per the Kosok-Reiche hypothesis) than chance. The same sort of analysis had been used on Stonehenge previously, discovering that it was built with an astronomical basis in mind.
This, too, has been challenged. It has been claimed that the analysis does not take into account the differences in southern hemisphere constellation positions, nor that the Nazca could have entirely different sets of constellations. Since a constellation is only a vague representation and fully arbitrary based on where one chooses to put it in the sky and which dots to connect, this criticism is not invalid (though one questions if the two initiators of the hypothesis took them into account, also). On the other hand, it has been pointed out, with the vast number of lines and positions of the figures, finding some sort of correlation with some sort of astronomical "sets" or objects seems highly possible without intention involved.
The best that can be said about that is "maybe," without strong supporting evidence.
Aliens
Might as well get it over with.... The "alien airport" connection is usually given to Swiss writer Erich von Däniken, though it was originally proposed in a 1955 issue of Fate magazine (which should suggest the "scientific" basis for such claims)1 and made popular in the sixties by the writers of a book titled The Morning of the Magicians. Best known for his books on the paranormal and extraterrestrials, particularly the 1970 Chariots of the Gods: Unsolved Mysteries of the Past (originally titled Erinnerungen an die Zukunft, "Memories of the Future"), he advanced what is referred to as the "ancient astronaut" theory.
The "theory" (obviously not the scientific definition of the word but the more colloquial one) is basically that all the ancient cultures of the world were visited by and "helped" along to an extraordinary degree culturally, socially, and—especially—technologically. Even the mythology of ancient peoples is based on these "visitations." These astronauts came to earth aboard their "chariots" (presumably to the poor, ignorant primitves that needed an interstellar shot in the arm) and worked with the people, instilling knowledge and helping them create what was necessary to advance. The "astronauts" are the ones that directly and indirectly created the great civilizations of Central and South America and Egypt (as noted in the aside, suggesting a strong racial bias, if not full-blown racism—whether aware of it or not—since the "white" or light-skinned civilizations needed no help from the "great old ones" from outer space).
According to von Däniken, the lines were made as a sort of airfield to help the aliens land. Of course, this brings up more problems than it (supposedly) explains.
First, for a place meant to be an airfield, the area is vast. This would suggest the intrepid astronauts were either coming in legion, couldn't land very well (needing the extra space and lots of lines for guidance), or had extra large vessels. Perhaps, these highly evolved technologically superior beings need more runway space than the space shuttle to land. Since there is no evidence for landings at all, none of this can be supported by anything other than speculation (as indeed all the "alien" claims).
Second, the amount and diversity of the "artwork" would seem enough to cause confusion. An airstrip, even one supporting large numbers of aircraft, does not need such markings. So why the excessive elaboration? Mere ornamentation would seem to add to the confusion for what is asserted to be something made for practical use. An attempt to explain away some of the difficulty there has been to suggest that the biomorphs and ornamentation were added afterward by the Nazca, hoping to entice the return of the benevolent benefacters. When this failed, the lines became infused with mythological meaning. But this is just speculation used in an attempt to justify previous unsupported speculation.
Third, the lack of evidence for landings, itself. Given the climate and the way it has allowed the preservation of the lines over a couple thousand years, it seems odd that there was no preservation of landing evidence. If (as I imagine a pro-astronaut "theorist" might counter), the reason is due to the technology used, then that brings up the first question as to why the vast area was necessary.
Of course, rather than pile speculation upon speculation, in order to prop up a "theory" that rests its case primarily on ancient myths and some "suggestive" pottery artwork, one might try considering other possibilities—that require less speculation and may have supporting evidence.
Flying Nazca
Before getting to the better accepted ideas of "why," there is an interesting idea to note. Forgetting the outer space claims and becoming a bit more terrestrial, the question arises about why the figures are not visible to those on the ground but to "those" in the air. The presumption being that they were made to be viewed. Some suggest that, perhaps, the Nazca were able to suspend themselves in the air via "balloons" (that American Indian culture had attempted and/or succeeded at this is not unknown but is generally dismissed due to lack of any evidence). Interestingly, some of the primary evidential support for this—pictures on pottery that seem to resemble balloons or kites—is little different than von Däniken's.
Other evidence that suggested this possibility to researchers was the existence of large, circular "burn pits" found at the end of some of the lines. It was thought they might signify a launching place for hot air balloons. In 1975, an experiment was devised.
A balloon was fashioned with implements that would have been available to the Nazca and made out of material they would have been able to make. With a "crew" of two (in a gondola made of reeds), the balloon reached a height of about 400 feet (122m), then landed after cooling off three minutes later. Unmanned, it rose again and reached 1200 feet (366m) and traveled a couple miles. It was aloft for a total of 14 minutes, which, according to the researchers, proves they could have done it. Of course, no evidence exists to sufficiently support the conclusion that they did (or even if they did, that it had anything to do with the lines).
Water and Religion
One way to determine possible meanings and intentions can be through finding correlation between other, especially related, cultures. The Inca civilization rose later than Nazca, so similarities could be evolved forms of Nazca ideas and practices—the Inca capital of Cuzco is only about 155 miles away (250 km).
One theory came from studying what appear to be striking similarities between the two. It involves what is known as the ceque system:
The city has four roadways or suyus leading out to the most remote areas of the Inca kingdom. And according to Spanish chroniclers, each of the roadways were couched within 41 imaginary straight lines called ceques, which radiated outward from Coricancha, a temple in Cuzco and the center of the Inca universe. The ceques were specified by actual physical sacred places or huacas—some 328 of them, eight or nine of which were arranged on each ceque. The last huacas of many ceques were located at underground water sources of Cuzco's underground irrigation system.
The system also functioned as a calendrical system, each huaca representing a day in the agricultural year. Ceques also could be used as astronomical sight lines. They were also routes of pilgrimage. When studied, it was found that Nazca lines also appear to radiate out from certain centers. They then measured about 800 of the straight lines and found the centers were quite similar, "[consisting] of a natural hill or low mound topped by a rock cairn that may have served as an identifying marker." They found that a majority of the lines connect to the hills.
Further, the lines seem to end in the large trapezoidal figures, whose axes seem "oriented along the water sources, with the skinny end pointing upstream about two-thirds of the time." It would seem that, even if the ceque theory is wrong or a bit off, the relation to water is a key to the purpose of the lines. This should hardly be a surprise (viewing it in this context), since any agricultural society is highly dependent on rainfall and/or access to water for survival. A society in a desert climate like the Nazca would be even more because of its scarcity.
Another related theory, by archaeologist Johan Reinhard, is that the lines were "sacred pathways" used for worshipping the source of the water—whether actual, as the mountains, or symbolic, as in invoking the deities responsible (generally the mountain ones). It seems, then, noteworthy that there are "images of humans [that] grace the steep hillsides at the edge of the desert" (skepdic.com). A possible way that this worship was accomplished was by walking the lines (the width of the lines is similar to that of footpaths)—by walking, tracing, the paths, a person would being invoking the spirit of the figure in some way. Plausible, given that the figures are almost all made of continuous lines. Conclusive? No.
The animals would be "forms taken on by the mountain gods, which are still worshipped today in Andean culture." And according to Reinhard, "each of the animal figures depicted has some correlation to water."
Another idea of his that attempts of explain the "why" can be related to either of those (even to the von Däniken nonsense if one wishes) or none. It tries to explain the scale on which they are "drawn." It is a simple concept—these figures are meant to be seen by the gods and the great gods (mountain deities or not) tend to be "above." The lines, then, are designed for those being worshipped to better seen (not an uncommon aspect of some religious creations). While, again plausible, it is far from conclusive—though speculation is far less than "alien astronauts" and grounded in concepts and beliefs seen in similar cultures. Reinhard admits as such.
Conclusion?
As for question #1, it has been more than adequately demonstrated the "how" they would have been built and that no "outside" source of knowledge or tools was needed.
Unfortunately, there is no clear conclusion or answer to question #2. It does seem safe to say that the symbols are related to water and religion, two things that were probably paramount in their lives. And given the number and scale of the creations as well as the amount of time and effort they would have required, the lines were probably similarly important to the Nazca.
It is the specifics that continue to puzzle researchers and scientists—the "what exactly"s. Something we may never quite know.
1A magazine (still extant) founded in 1948 that brags to have "for over 50 years...brought you true reports of the unusual, mysterious, and the paranormal from around the world. These are reports that reveal a 'reality' that is deeper and richer than commonly taught in our schools." This editorial vision has been maintained since the beginning. In an internal memo by one of the founders describing what the magazine "was":
I think FATE is a book of magic. When we were kids we believed in fairies and brownies and ghosts and hobgoblins and miracles. I think FATE shows, or should show, that fairies and brownies and hobgoblins and miracles exist today. (www.fatemag.org)
According to the magazine's new publisher, the "secret formula" is "information plus knowledge, enriched by imagination, excited by emotion, all under the direction of mind." Of course....
(Sources: "Discovery Channel Canada" exn.ca/mysticplaces/nazca.cfm all quotes from here unless otherwise noted, skepdic.com/nazca.html, www.britannica.com, www.fatemag.com/announce.phtml)