The Royal Road It’s one thing to conquer many lands. It’s another thing to keep control of what you’ve conquered. Remember how the ancient Romans held their empire together? They built roads all across it.

The roads made it possible for government officials to travel around the empire. Roads also encouraged trade. Most importantly, the roads allowed the army to travel quickly. This way, they could put down a rebellion or enforce the emperor’s rule.

The Inca knew nothing of ancient Rome. But they too were great road builders. Their Royal Road stretched over two thousand miles. It ran from the northern end of the empire to the southern tip. It was the longest road in the world until the 1800s.

The Royal Road was twenty-four feet wide in most places. Although it crossed mountains, valleys, deserts, and swamps, long stretches were straight as an arrow. Markers measured distances along the road. Trees shaded the road. A canal provided water for travelers. There were even roadside storehouses where travelers could get food at the end of the day.

Parts of the Royal Road were made of packed dirt. Other parts were paved. Inca engineers fitted paving stones together like pieces of a jigsaw puzzle. Modern builders use mortar, a cement-like material, to keep stones together. The Inca did not use any mortar. Instead, they cut stones so exactly that they fit together snugly.

The Royal Road shows the great skill of Inca builders. These builders had no earthmoving machinery. They did not have horses or oxen to pull wagons. They did not even have the wheel. Everything was done by hand. Yet the Inca were able to build roads so sturdy, not even heavy rains or flash floods could destroy them.

The Royal Road was the main Inca road, but there were others. At every valley, east-west roads crossed the Royal Road. The Royal Road was like the spine. The crossroads were like nerves branching out from it. This network of roads linked all parts of the empire together.