The ancient Inca built an empire in South America as grand as ancient Rome. At its height, it was home to more than 10 million people, spread over 2,500 miles (4,023 km). Across their vast kingdom, the Inca transformed steep mountain slopes into terraced gardens. They constructed a highway system 25,000 miles long (40,233 km). End to end, these roads would stretch all the way around the Earth! This system included suspension bridges, some more than 150 feet long (46 meters). The Inca even built the spectacular cloud city of Machu Picchu, on a mountain peak 1.5 miles (2.4 km) above sea level. Yet when we read about the Inca today, we’re often told that they never developed a system of writing.
Or did they? For years, scientists have wondered whether intricately knotted strings prepared by the
