Recorded accounts from the 16th century A.D. detail practices of state-regulated sun worship during Inca times, and related social and cosmological beliefs. These speak of towers being used to mark the rising or setting position of the sun at certain times in the year, but no trace of the towers has ever been found. This paper reports the earliest structures that support those writings.

At Chankillo, not only were there towers marking the sun's position throughout the year, but they remain in place, and the site was constructed much earlier – in approximately the 4th century B.C.

"Archaeological research in Peru is constantly pushing back the origins of civilization in the Americas ," said Ivan Ghezzi, a graduate student in the department of Anthropology at Yale University and lead author of the paper. "In this case, the 2,300 year old solar observatory at Chankillo is the earliest such structure identified and unlike all other sites contains alignments that cover the entire solar year. It predates the European conquests by 1,800 years and even precedes, by about 500 years, the monuments of similar purpose constructed by the Mayans in Central America ," reports Playfuls.

One of the biggest mysteries of Chankillo was the purpose of a low ridge composed of 16 relatively small stone towers which together formed an artificial toothed horizon for no apparent reason.

However, Ghezzi and Ruggles show that the gaps formed between the towers match the annual rising and setting arcs of the Sun while it dips below the horizon during the winter and summer solstices.

The line of towers, which range in height from about 6ft to 20ft, were built along a north-south axis and can be viewed full-on from two other stone positions, one to the east and one to the west of the ridge.

"Viewed from the two observing points, the spread of the towers along the horizon corresponds very closely to the range of movement of the rising and setting positions of the sun over the year," say Ghezzi and Ruggles in their study, informs Independent.