Highly trained Incan accountants known as quipucamayocs managed an entire continent-spanning empire without a written language by tying intricate knots into colored alpaca wool…

A closer look

Running an empire of ten million people without a single written word sounds mathematically impossible until you look at the quipu. The Incas used a highly complex binary-like system of knotted strings to store vast amounts of data. The quipucamayocs could literally read the strings by feeling the knot types, colors, and spatial positioning. It was essentially an ancient Excel spreadsheet made of llama hair that completely completely baffled the invading Spanish conquistadors.