Guardians of an Incan Mystery

The small town of Rapaz high in the Andes of Peru seems to be guarding an important 500 year old ancient Incan mystery. as reported by Simon Romero of The New York Times

"Archaeologists say the Incas, brought down by the Spanish conquest, used khipus — strands of woolen cords made from the hair of animals like llamas or alpacas — as an alternative to writing. The practice may have allowed them to share information from what is now southern Colombia to northern Chile.

Few of the world’s so-called lost writings have proved as daunting to decipher as khipus, scholars say, with chroniclers from the outset of colonial rule bewildered by their inability to crack the code. Researchers at Harvard have been using databases and mathematical models in recent efforts to understand the khipu (pronounced KEE-poo), which means knot in Quechua, the Inca language still spoken by millions in the Andes."  ...(Cont.)... 

More:
String, and Knot, Theory of Inca Writing