Scientists investigating the archaeological complex of Incahuasi, south of Lima, have uncovered 25 well-preserved quipus.
The 600-year-old strings are an example of the technology of the Inca civilization, which never developed a written language.
Quipu – also called “khi-pus” or “talking knots” – are made up of colored spun thread, and sometimes, llama or alpaca hair.
The ornately knotted strings are thought to have helped in record-keeping, when authorities wanted to monitor items such as taxes and population.