Due to the mountainous terrain, it was difficult for them to farm. Similar to the Aztecs, they also invented a way to farm in their harsh environment. The Incas came up with the idea of ​​terraces (Document 6). These were steps or flat areas carved into the mountains that made farming easier. Another agricultural achievement of the Incas was the widespread construction of irrigation canals. As the empire expanded, there was a need for more agricultural land, but there wasn't always a source of water available. The Incas cultivated corn, cotton and squash. Garciasco de la Vega, speaking of agriculture in the Inca Empire, said: "Engineers showed great intelligence and skill in providing water for crops since only sparse sections of land could grow corn" (Document 4). Their success with irrigation helped them expand their empire. Without it, it would be harder for them to survive in a growing empire. Just like the Romans, they connected their empire through an extensive road system that included long suspension bridges over mountains. This road allowed the empire to better protect itself because it was a quick way for armies to travel from one end of the empire to the other (Document 5). These roads were both an engineering achievement and a governmental achievement. It was an engineering feat because they built roads and bridges from present-day Ecuador to the southern part of Chile. The government had to be strong, similar to the construction of the pyramid