Chankillo Archaeoastronomical Complex

Chankillo Archaeoastronomical Complex

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Site and Significance
A Unique Ancient Observatory

Archaeological evidence indicates that Chankillo, located in the coastal desert of Peru near the Casma-Sechín river basin, may be the earliest known astronomical observatory in the Americas. Built over 2,300 years ago, the site features a plaza, Thirteen Towers that align on a ridge, and a Fortified Temple surrounded by barricades and defensive walls with false entrances to deter unwelcome visitors. Recent excavations indicate that Chankillo was occupied for a relatively short period of time between the mid-fourth century BCE and the early first century CE, but was subsequently abandoned, and remained largely forgotten until the nineteenth century.

Chankillo is unique among ancient observatory sites because of its two observation points; similar sites around the world contain only one point of astronomical alignment, which does not provide the measurements needed to track the passage of time over a full year. The Thirteen Towers of Chankillo, situated between two observation platforms, span the entire annual rising and setting arcs of the sun, which gradually shifts along the horizon over the course of a year.

By watching the sunrise or sunset from the observation platforms, the inhabitants of Chankillo would have been able to accurately determine the date within one to two days of precision and could therefore regulate the occurrence of seasonal events, including planting and harvest times, as well as religious festivals. Archaeological evidence at Chankillo also suggests that sun worship existed in the Andes around two millennia before the well-known sun cult of the Inca Empire.