The first Inca then traveled to the summit of a nearby hill called Huanacauri, where one of them was turned into stone and became an important shrine.
Magli argues that certain structures at Machu Picchu symbolize important landmarks of this journey.
For instance, a disorderly pile of stones represents the underground "void" that the first Inca traveled through.
"Pacha-Mama, or Mother Earth, was associated with disorder," Magli said.
Similarly, a plaza at Machu Picchu represents Tampu-tocco, and a stone pyramid at the site doubles for the Huanacauri hill, Magli added.
Visitors to Machu Picchu enter through a gate at the complex's southeastern end. The layout then coaxes them northwest. This, Magli said, is no accident.
In his study, published on the Web site arXiv.org, Magli argues that Machu Picchu's southeast-northwest layout is meant to replicate the path of the sun across the sky in Inca country, averaged over the course of a year.
Southeast-northwest is also the direction traveled by the first Inca during their mythic journey—again, likely influenced by the sun, which was worshipped as a god.
As a sacred site, Machu Picchu may have been open to commoners and highborn alike, much like a known Inca pilgrimage destination on the Island of the Sun, Magli said.
"As far as we know, the pilgrimage to the Island of the Sun was open to all, but not all were admitted in the innermost sanctuary," he said. "Perhaps the same occurred in Machu Picchu."
Archaeologist Richard Burger of Yale University is unconvinced.
Magli "does make the argument for the importance of celestial movements in relation to specific buildings," said Burger, who was not involved in the study.
Still, Magli's arguments "are not incompatible with the interpretation of Machu Picchu as a tropical retreat for the royal court any more than the presence of religious art and architecture at Versailles is incompatible with its role as a royal palace."
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