Thirteen Towers of Chankillo, Peru

The enigmatic, 2,300-year-old Chankillo ruins, seen from space. The Thirteen Towers — with each tower spaced about five metres apart — are thought to be part of a solar observatory to mark the solstices and equinoxes.

Located in the Peruvian coastal desert at the Casma-Sechin Oasis, stands the incredible monumental complex of Chankillo, also known as Chanquillo, which extends across four square kilometers. The ancient archaeological site consists of a fort located on hilltop and thirteen solar observatory towers, as well as residential and gathering areas. It was occupied for a relatively short period of time – between the mid-fourth century BC and the early first century AD.

Located between two observation platforms, the thirteen astronomical towers span the entire annual rising and setting arcs of the sun, which shift north and south along the horizon gradually over the course of a year. What makes Chankillo so important is the fact that, according to archaeologists, Chankillo may be the earliest known astronomical observatory in the Americas, built some 2,300 years ago. The Incas, also well known astronomers, observed the sun and the stars, but they did so many centuries later.

Research has shown that the astronomical alignments seen at Chankillo were, and still are, incredibly precise. The towers have been known about for a long time but their astronomical value had not been widely realized until Ivan Ghezzi and Clive Ruggles undertook detailed research at the site in 2007.

Archaeologists suggest that the inhabitants of Chankillo would have been able to determine the date with an accuracy of +/- two to three days by observing the sunrise/sunset from the correct observational platform. On the winter solstice, the sun would rise behind the further tower on the left and then over time, would rise behind each of the towers until it reached the furthest tower on the right some six months later on the summer solstice, marking the passage of time. Other ancient sites known for astronomical observatories contain only one point of astronomical alignment which does not provide enough information for an accurate measurement of time over one year.

The towers at Chankillo, which are spaced at intervals between 4.7 and 5.1 meters, vary in shape and size, ranging from 70 to 130 meters in width and up to 6 meters in height.  According to archaeologists, at the time the towers were constructed they were completely flat on top. [To view the thirteen towers of Chankillo on Google Maps, select Google Earth’s ‘Fly To’ option and enter latitude: 9 33 40.27 S and longitude: 78 13 38.53 W.]

The walls of this ancient site were once shiny white, with paintings and figures decorating the monuments. The structures found at Chankillo were built of shaped stone and mortared walls, a combination that reflects the surroundings of this coastal desert and incredibly beautiful environment in Peru. Apart from observing the Sun, the Chankillo observatory would have aided the builders of Chankillo to know the best time to plant and harvest of crops.

The most puzzling aspect of Chankillo is, who built this incredible complex? Archaeologists no almost nothing about these ancient builders who paid tribute to the sun and stars, constructing the first ever solar observatory in the Americas.

Like many other ancient cultures that have worshiped the sun and the Sun God, Chankillo wasn't much different, as the towers were probably built, not only as a calendar and observatory, but also as a place with which to celebrate their mystical connection with the sun.  "If you were just measuring seasons, there would be no need to make such great structures," says Ghezzi . "The idea was to transmit a political and ideological message about a ruler's close relationship with the sun."