What they are
On the stone-strewn plateau (pampa) between the Nazca and Ingenio valleys, the desert’s surface is a dark varnish of oxidised pebbles over pale clay. Remove the pebbles and you draw a line visible for centuries — for the Nazca desert is among the driest places on Earth, nearly rainless and windless enough to preserve a footpath forever. With this one trick, the Nazca culture (flourishing c. 100 BC-650 AD, heirs to the Paracas) covered hundreds of square kilometres with geoglyphs: dead-straight lines running kilometres, trapezoids and spirals, and the celebrated animal figures — hummingbird, monkey with spiral tail, spider, condor, killer whale — each drawn as a single continuous path, sized up to 370 metres.
They were noticed from the ground occasionally (the conquistador-chronicler Cieza de León mentions desert “signs” in 1553) but entered science only when commercial aviation began overflying the pampa in the 1920s-30s. The Peruvian archaeologist Toribio Mejía Xesspe reported them in 1926; the American Paul Kosok, watching a solstice sunset align with a line in 1941, called the pampa “the largest astronomy book in the world”; and his assistant Maria Reiche spent the next five decades mapping, sweeping, and fiercely guarding the lines — the “Lady of the Lines,” who lived beside and for them until her death in 1998.
What they were for
Kosok’s and Reiche’s astronomical calendar theory has fared poorly — statistical checks find little beyond chance alignment. The working consensus assembled since treats the lines as ritual landscape: many figures and trapezoids are walkable single paths, worn by feet, furnished with pottery offerings and platforms; lines converge on water sources and radiate from ray centres; and the imagery matches the water-and-fertility iconography of Nazca ceramics — all in a society whose existential problem was rivers that ran dry, and whose engineering masterpiece was the puquios, spiral-entranced aqueducts still functioning today. The lines, in short, were probably made to be walked and seen by gods, not read from the air.
Which did not stop the 20th century preferring aliens: Erich von Däniken’s runway fantasies made the “astronaut” figure famous and the pampa a byword for pseudo-archaeology — the recurring colonial reflex, as at Great Zimbabwe, of crediting anyone but the locals.
Fragile forever
What drought preserved, tyres destroy: the surface records every track, and the lines have survived the Pan-American Highway (which bisects a figure), a 2014 Greenpeace publicity stunt that scarred the hummingbird’s margins, and repeated truck incursions. Drones and machine-learning surveys, meanwhile, keep enlarging the corpus — hundreds of smaller, older figures have been identified since 2018 — on a plateau that is still, plainly, not done being read.