Chankillo: The world’s oldest astronomical observatory
According to a study published by archaeologists Ivan Ghezzi, Universidad Católica del Perú and Charles Ruggles, Leicester University UK, there is evidence of the oldest known observatory in the world. They stated that "The towers of Chankillo provide us with evidence of the first solar observations and of the existence of advanced cults to the sun, 2,000 years before the cults made by the Incas from Cusco."

Before now, based on the references of the first Spanish chroniclers, it was believed that the first observatories were in the Coricancha region, near Cusco and were constructed by the Moche culture, 600 years after Chankillo. Chankillo was constructed when one of the major religious centers collapsed, Chavin de Huantar, between 200 and 300 B.C.

Located some 15 km south of Casma, about 400 km north of Lima, Chankillo is made up of a fortress strategically situated on the top of a hill, composed of 3 concentric oval shaped thick rock walls (with 5, 4, and 3 entrances respectively from the outer to the inner). These leveled doorways lead to elaborate corridors, its roofs are made with thick algarrobo wood that still support the weight of the wall above. Surrounding these concentric circles are 2 round structures and 1 circle. The C14 analysis of the wood shows us that the wood is 2,300 years old.

In the front of this fortress there is a group of 13 towers, rising in a row from North to South on the top of the Chankillo hill, they indicate with precision the yearly movement of the sun, the solstices and equinoxes.

Different sources reveal the andean calendar divided in 13 months of 28 days each, with 4 weeks of 7 days, corresponding to the four moon phases. Total 364 days. The day missing is dedicated to the sun’s worship. This day is named Inti Raymi (quechua) or Willka Uru (aymara) this is the beginning of the New Andean Year, June 21st, the winter solstice day.

June solstice is the moment when the sun reaches its lowest point, when sun rays hit at its maximum low angle the southern hemisphere lands of earth. This stage corresponds to the culmination of winter and is the moment chosen to celebrate the New Andean Year because it marks the end of the harvest season and the begin of a new planting season. The sun will provide the energy for a good harvest.

Each tower measures between 2 and 6 m in diameter and is separated by 4.7 and 5.1 m. They are all aligned on the edge of the hill. Each structure has 2 stairways, on the North and South sides, that lead to the top of the tower. For a long time nobody understood the presence of this row of towers which looked like the spines along the back of a dragon.

Since the XIX century it was speculated that the row of 13 towers could be a lunar trace, but nobody decided to follow that hunch, said Ghezzi, who decided to test the idea while studying military structures, dating back to 400 years B.C., in a nearby area.

The key came from the discovery of 2 observing points, situated some 200 m from the ends of the row of towers, both decorated with relics known as sacrificial material. Following the movement of the sun from both points, archaeologists noted that the distribution of the towers, constructed at regular intervals, adjust to the path of the stars. They say,that if today the position of dawn coincides with the third tower, after some time it will coincide with the fourth, afterwards with the fifth until the cycle the structures mark is complete.

The tower located farthest East was in bad condition, but the one located to the West has maintained most of its structure and permitted scientists to determine its function. Both observing points were positioned in a such way that in the Summer and Winter solstices the sun rises and sets above the towers, forming a line that clearly defines the solar year.

Thousands of people could have gathered to observe impressive solar events. These sunrises and sunsets could have been used in accordance with a political agenda, says Ivan Ghezzi As example during June's winter solstice (the shortest day of the year) the sun rises just left of the most septentrional (Northern) tower

We have to find other reasons to explain why a group of people went that far to construct monumental towers on the top of a hill.

For this scientist the discovery of such an old observatory it is not a surprise. He has stated that Perú is one of the unexplored archaeological frontiers of the world.

Ghezzi said he knows very little about the people that made Chankillo, but he is sure they preceded the Incas by many centuries.

The archaeological study revealed that in the construction, offerings were made to figures of clay warriors with ornaments that seemed to be signs of status. This suggests ritual practices as well as the existence of social classes. The sun adoration might have helped to legitimize the authority of an elite class, declared the archaeologist.

Astronomical rituals long before the Incas? Is this more evidence that our history is older than was thought? Is this evolution or involution? We hope data and probes continue appearing in order to extend our historical frontiers even more, giving evidence of our authentic roots. Who knows if we are all wrong...

Bike trips to Chankillo in 2008
Based on this interesting information we have planned a bike trips to Chankillo to be present on the solstices and equinoxes days and observe the sun rising from the oldest observatory in the world just like our ancestors did very long ago.

June 21st:             winter solstice
September 22nd:    equinox
December 21st:      summer solstice

Other dates are also available but these are the most important due to their astronomical significance

Duration: 2 days 1 night
Level: 1. Easy

Itinerary:
From Lima to Casma round trip by bus. From Casma to Chankillo and surroundings by bike.

Departure: June 21st            Return: June 22nd
Departure: September 21st    Return: September 22nd
Departure: December 21st     Return: December 22nd.