Thirteen Towers of Chankillo

Scientists have declared some ruins in Peru to be the oldest space observatory in the world. Built 2300 years ago, the Thirteen Towers of Chankillo indicate how well early peoples understood the basics of astronomy.

In a report in the current issue of the journal Science, a Peruvian archaeologist and a British archaeoastronomer wrote that the 13 towers, varying in height from 6 to 20 feet and extending 1,000 feet, are clearly visible from an imposing complex of concentric circles of relatively well-preserved walls enclosing ceremonial buildings. They said the position of the towers in relation to observation points inside the walled complex was firm evidence that this was a place for solar study in calendar-making and ritual ceremonies and feasts of sun cults.

It does make Stonehenge look pretty small.