The Nazca Lines
Partially explainedSummary
On the desert plateau between Nazca and Palpa, people removed the weathered surface gravel to expose the lighter ground beneath. The resulting figures and lines were made between roughly 500 BC and AD 650, by the Paracas and Nasca cultures. None of that is in dispute.
What the geoglyphs were for is a narrower question than the popular framing suggests. Some proposals, alien landing strips among them, have been rejected. In 2024 a survey that used a machine-learning model to generate candidates for archaeologists to check on foot raised the count of known figurative geoglyphs from 430 to 733, and established a measurable difference in size, subject and placement between two types, from which its authors argue two different purposes.
What is documented
How they were made. In UNESCO’s description, by "removing the overlying weathered gravels to reveal the lighter bedrock". The 2024 survey’s drawings show the same thing at the scale of a single figure: stones removed to expose lighter ground, and the removed stones piled up. This is established and uncontroversial.
When. UNESCO gives the span as 500 BC to AD 500, though two statements on its own listing disagree with each other, one giving a wider range. Independent absolute dating exists for the geometric lines: optically stimulated luminescence dating of quartz buried during construction near Palpa put that work between AD 400 and 650. The 2024 survey assigns line-type geoglyphs to roughly 100 BC to AD 650 and relief-type to about 100 BC to AD 50 or earlier. Relief-type geoglyphs currently rest on iconography and technique rather than on absolute dating.
The 2024 survey, and what the machine actually did. A model was fine-tuned on known relief-type geoglyphs and run over ten-centimetre aerial imagery to produce a probability map. It generated 1,309 candidate locations. Archaeologists then screened an average of thirty-six machine suggestions for each likely candidate and walked the ground between September 2022 and February 2023, checking about a quarter of the candidates. That field work confirmed 303 new figurative geoglyphs. The reported effect is a sixteenfold increase in the rate of discovery, which is a claim about speed, not about autonomy.
The counts. Before the survey, 430 figurative geoglyphs were known: 380 relief-type and 50 line-type. All 303 new confirmations were relief-type. That brings the totals to 683 relief-type and 50 line-type.
The split the survey measured. Relief-type geoglyphs average about nine metres across; line-type average about ninety metres in length. Relief-type depict humans or human-modified things in 81.6 per cent of cases; line-type depict wild animals in 64 per cent of cases. Relief-type lie on average forty-three metres from trails; line-type lie on average thirty-four metres from linear and trapezoidal geoglyphs. These are measurements, and they are what the functional argument is built on.
Visibility, as a field finding. The 2024 survey reports that "All individual geoglyphs that do not form geoglyph groups have been found to be visible from the trails", and concludes that relief-type geoglyphs "were objects to be viewed while walking along the trails".
They were rediscovered before the aerial surveys. Sakai and colleagues date the modern rediscovery to the early twentieth century, citing Toribio Mejía Xesspe’s paper in the proceedings of the 27th International Congress of Americanists, published in Lima in 1940. Field surveys aided by aerial photography began in the 1940s.
The figures can be made without an aerial view, and this was demonstrated. In August 1982 Joe Nickell and five helpers reproduced the 440-foot Nazca condor on a Kentucky field using only ropes marked in Nazca-derived units, a wooden T-square, stakes, twine and powdered lime. Plotting and staking took about nine hours; marking took about a day. No aerial view was used to design or guide it, and an aircraft was used only to photograph the finished result. A wildlife biologist taken to the site to test it identified the figure as a bird.
Leading explanations
Two functions, by geoglyph type (Sakai and colleagues, 2024; hypothesis, untested). That relief-type geoglyphs, being small, close to trails and overwhelmingly depicting humans and human-made things, shared information about human activities with individuals or small groups; and that line-type geoglyphs, being large, grouped with linear and trapezoidal figures and mostly depicting wild animals, were built and used by the community for ceremonial purposes. The underlying measurements are solid data. The functional inference drawn from them was published in 2024 and has not been independently tested.
Sacred space and ritual movement (Silverman, 1994, and others; the predominant opinion). That the linear geoglyphs "were an integral part of the Nasca sacred space", the view Sakai and colleagues describe as predominant. Some lines are associated with pilgrimage routes to and from the ceremonial centre at Cahuachi, with the territory of particular social groups, or with subterranean water sources. UNESCO describes the lines as believed to have had ritual astronomical functions, and notes that some tracks appear to have been laid out to accommodate large numbers of people.
Calendar and astronomy (one of five hypotheses in Aveni’s 1990 survey; disputed). That the lines marked astronomical events or mapped the sky. The version in which the animal figures correspond to constellations has been criticised as resting on a Western view of the constellations, since no such constellations are recorded ethnohistorically or ethnographically.
Landing strips for visitors from elsewhere (von Däniken; rejected). Joe Nickell notes that the idea "is not his own and it originated in jest": the lines were nicknamed prehistoric landing fields when first viewed from the air. Maria Reiche’s objection, as Nickell reports it, was that the ground is quite soft: "I’m afraid the spacemen would have gotten stuck."
What the popular version gets wrong
"They can only be seen from the air, so the makers never saw them." False. Joe Nickell noted in 1983 that this "is not quite true, certainly not of the smaller figures", and that "even the large drawings can be appreciated to some extent from the ground". Relief-type figures tend to sit on hill slopes, where they can be seen from a distance. And the 2024 field survey reports that every individual geoglyph not in a group was found to be visible from the trails.
"Figures this large could not be laid out without an aerial view." Demonstrated false by physical replication in 1982, using rope, stakes, a wooden T-square and lime, with no aerial view used in the making.
"An artificial intelligence discovered hundreds of hidden figures." The model generated 1,309 candidates. Archaeologists screened about thirty-six suggestions per likely candidate and confirmed 303 by walking the ground over six months. The documented contribution is a sixteenfold increase in the rate of discovery.
"Nobody has any idea what they were for." Overstated. The landing-strip idea is rejected, and a reading of the lines as part of a sacred, ritual landscape is the predominant opinion. What is genuinely open is the function of particular classes of geoglyph.
Current status
Partially explained. This is not a mystery about origin. The construction method is established, the cultural attribution is established, and there is independent absolute dating for the geometric lines. What remains open is narrower: what specific social function each class of geoglyph served. The 2024 survey changed the evidence available for that question, raising known figurative geoglyphs from 430 to 733 and establishing a measurable split in size, subject and placement between the two types. Its two-function reading would move toward acceptance if an independent team reproduced the trail-proximity and motif statistics on a separate sample, if direct absolute dates were obtained for relief-type geoglyphs specifically rather than inferred from iconography, and if excavation recovered use-related deposits consistent with small-group viewing. It would be weakened if relief-type geoglyphs proved to date from a markedly different period, or if the trails proved to postdate the figures beside them.
Sources
- Sakai, M., Sakurai, A., Lu, S., Olano, J., Albrecht, C. M., Hamann, H. F. and Freitag, M. (2024). "AI-accelerated Nazca survey nearly doubles the number of known figurative geoglyphs and sheds light on their purpose." Proceedings of the National Academy of Sciences, 121(40), article e2407652121, 23 September 2024. Read as the full-text PDF in an institutional repository. Source of every count, size, distance and motif proportion above, of the construction drawings, and of the review of earlier hypotheses and of the rediscovery.
- Yamagata University (2024). News release on the survey, 24 September 2024. Source of the 1,309 candidates, the thirty-six suggestions screened per candidate and the sixteenfold figure.
- Rink, W. J. and Bartoll, J. (2005). "Dating the geometric Nasca lines in the Peruvian desert." Antiquity, 79(304), pp. 390 to 401. The AD 400 to 650 result was read from the publisher’s record; the article body is paywalled, so the error margins are not stated here.
- Nickell, J. (1983). "The Nazca Drawings Revisited: Creation of a Full-Sized Duplicate." The Skeptical Inquirer, Spring 1983, pp. 36 to 43. Read as a scanned copy. Source of the replication account, of the observation that the figures can be appreciated from the ground, and of the landing-strip history and Maria Reiche’s objection.
- UNESCO World Heritage Centre. "Lines and Geoglyphs of Nasca and Palpa", property 700, inscribed 1994. Source of the construction description, the distance from Lima and the description of the lines’ believed ritual functions. The introduction and the brief synthesis on that page give conflicting dating spans, which is why this record gives a range.
- Aveni, A. F., ed. (1990). The Lines of Nazca. American Philosophical Society. Silverman, H. (1994). World Archaeology, 26, pp. 1 to 18. Silverman, H. and Proulx, D. A. (2002). The Nasca. Blackwell. Cited through Sakai and colleagues for the earlier hypotheses; not retrieved directly.
- Mejía Xesspe, T. (1940). Actas del 27 Congreso Internacional de Americanistas, Lima. Cited through Sakai and colleagues for the modern rediscovery; not retrieved directly.
Last reviewed: November 2026. Records are provisional. Where the evidence changes, the entry changes. Found an error? Tell us.