These new findings make an important point about the Nasca lines: They were not made at one time, in one place, for one purpose. Many have been superimposed on older ones, with erasures and overwritings complicating their interpretation; archaeologist Helaine Silverman once likened them to the scribbling on a blackboard at the end of a busy day at school. The popular notion that they can be seen only from the air is a modern myth. The early Paracas-era geoglyphs were placed on hillsides where they could be seen from the pampa. By early Nasca times the images—less anthropomorphic, more naturalistic—had migrated from the nearby slopes to the floor of the pampa. Almost all of these iconic animal figures, such as the spider and the hummingbird, were single-line drawings; a person could step into them at one point and exit at another without ever crossing a line, suggesting to archaeologists that at some point in early Nasca times the lines evolved from mere images to pathways for ceremonial processions. Later, possibly in response to explosive population growth documented by the German-Peruvian team, more people may have participated in these rituals, and the geoglyphs took on open, geometrical patterns, with some trapezoids stretching more than 2,000 feet. "Our idea," Reindel says, "is that they weren't meant as images to be seen anymore, but stages to be walked upon, to be used for religious ceremonies."
Those ancient acts of worship have left their traces in the ground itself. Between 2003 and 2007 Tomasz Gorka and Jörg Fassbinder, geophysicists at the Bavarian State Department of Monuments and Sites, took measurements of the Earth's magnetic field on a trapezoid near Yunama, a village outside Palpa, and on other lines nearby. Subtle perturbations in the magnetic signal indicated that the soil had been compacted by human activity, especially around the platforms. Karsten Lambers, another member of the Nasca-Palpa Project, had meanwhile collected positional data and precise measurements of sight lines across hundreds of geoglyphs. The data showed that the trapezoids and other geometric shapes were constructed where they would be visible from a number of vantage points. The team concluded that they were places where "social groups acted and interacted, and spectators in the valleys and on other geoglyph sites were able to watch and observe."
Cerro Blanco, among the tallest sand dunes in the world, rises pale and stark out of the surrounding bowl of sere Andean foothills, dominating the physical and spiritual landscape of the southern Nasca valleys. For centuries the Andean people have worshipped deities embodied in mountains such as Cerro Blanco. According to Johan Reinhard, a National Geographic explorer-in-residence, the mountains have traditionally been associated—mythologically, if not geologically—with water sources. The Nasca potsherds littering the path to the summit of Cerro Blanco would suggest the connection runs deep into the past.