Summary:
- The Inca Empire, which ruled parts of South America centuries ago, used a complex system of knotted strings called "khipu" or "quipu" to record information and keep track of their empire.
- Khipu were made of colored cotton or camelid fibers, with knots tied in different patterns and positions to represent numbers, words, and other data.
- Researchers are still studying these intricate khipu to better understand the Inca's advanced record-keeping and communication methods, which were an important part of their sophisticated civilization.