Ancient Peruvian Sun calendar declared UN heritage site

Casma , Peru: A 2,300-year-old solar observatory in Peru, a structure of 13 stone towers built atop a hill and used as a calendar, was declared a Unesco World Heritage site on Tuesday.

The Chankillo observatory, built by an ancient civilisation about two millennia before the ascent of another well-known Sun cult -- the Inca empire -- allowed for remarkably accurate astronomical observations, according to recent studies. The walled, hilltop ruins some 400 kilometers (250 miles) north of Lima had long puzzled scientists.

Then in 2007, a study in the journal Science proposed the sequence of towers erected between 200 and 300 BC "marked the summer and winter solstices" and that Chankillo "was in part a solar observatory."