Chankillo; oldest known Solar Observatory in the Americas : The 2300 year old archaeological ruin that lies in a desert valley in Northern Peru contains 13 towers that align on a ridge. Towers functioned as a calendar using the rising and setting of the sun to mark not only equinoxes and solstices but even to define the precise time of the year within one or two days. The people who built this site seem to have worshipped the sun, 2,000 years before the Inca did. #archaeohistories