Talk about natural barriers! The Inca Empire had them all. The Empire covered a vast amount of space. At its height, the Inca Empire was 2,500 miles long, 500 miles wide, and home to 12 million people, connected by 14,000 miles of roads, many of which were paved. The Inca Empire was located on the western side of South America. Although the Empire was huge, it can be easily divided into three geographical regions - mountains, jungle, and desert.
Andes Mountains: The Andes Mountains run north to south. The Andes are the backbone of South America. They run close to the west coast for the entire length of South America - 4,500 miles! In some places, they measure more than 400 miles wide. In others, they measure about 100 miles across. These are not flat miles. The width is a series of very high mountain peaks. Here and there in the Andes, there are active volcanoes. The Andes are rich in minerals including gold, silver, copper, tin, iron, emeralds, and more! The Andes Mountains are very high. They are higher than the Alps or the Rockies.
The Incas made their home high in the Andes mountains. To move about, 11,000 feet above sea level, the Inca built bridges between mountain peaks and over deep gorges. These bridges were made of sturdy vines. The Inca never invented the wheel, and the commoners were not allowed on the roads, so the only travel over these bridges were the animals that hauled food, warriors, the road runners (who carried messages using a relay system), the nobles, and government officials.
The mountains dominated Inca society. The mountain peaks were worshiped as gods. The Andes created a natural barrier between the coastal desert on one side and the jungle on the other. The snow-capped mountains were full of deep gorges. The Inca built bridges across the gorges of heavily woven vines so they could reach all parts of their empire quickly and easily.
To stop invasion in any section of their empire, all they had
to do was burn two bridges, one on each side of a deep gorge,
which effectively captured their enemy in the middle. They did
not even have to kill them. They could walk away and let the
captured people freeze to death or be eaten by animals.
Amazon Jungle: On one side of the Andes was the Amazon jungle. The Incas must have entered the jungle occasionally, as they did know about the many valuable things that could be found in the Amazon, like wood and fruit and natural medicines, but they never established settlements there. They had no desire to live in the jungle. High in the Andes Mountains, the Incas expanded north and south instead.
Coastal Desert: Between the mountains and the Pacific Ocean is a coastal desert 2000 miles long and between 30-100 miles wide. The desert provided a wonderful natural barrier. Some scientists think it is the driest place in the world. It's not completely barren. There are fertile strips where small rivers and streams run off from the Andes mountaintops to the sea. Although there were a few tribes living along the coastal desert, the Incas were not one of them. They preferred their mountain home.