"We have references that Incas practiced solar observation, but none of those sites have been preserved," says the site's lead archaeologist Ivan Ghezzi of Yale University and the Pontifical Catholic University of Peru. "We don't have a single one of this complexity."
Though Spanish chroniclers described "sun pillars" used by the Incas to mark specific solar events, the physical remains of these pillars—likely destroyed during 16th-century anti-idolatry campaigns—have not been found. Archaeologists have uncovered the base of two pillars on an island in nearby Lake Titicaca, but the observatories in Chankillo appear more sophisticated than any of these Incan structures, says Ghezzi, who published his findings along with coauthor Clive Ruggles of the University of Leicester, in Science last month.
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