1. The Incas
Of the three Mesoamerican civilizations studied this unit, the Incas had the most important achievements. For example, they had an amazing system of roads. The Incas also had advanced medicine. Finally, they had maintained tight control over a vast empire. Admittedly, the Aztecs also had an amazing empire, Tenochtitlan, but the Incas had an even greater empire because of its size.

2. Road System
The Incas had an incredible system of roads. For example, they built roads across the length and width of their empire. Roughly 15,000 miles of road linked the entire empire together. The roads crossed through jungles, mountains and raging rivers. The Incas had a unique relay system of messengers called chasquis who carried knotted sets of string called quipus. The quipus were used as memory aids and they were passed on from chasqui to chasqui as they traveled along the roads. Using this efficient system, messages could travel over 250 miles a day.

3. Medicine
The Incas had remarkable advances in medicine. For example, they practiced a surgery called Trephination. Trephination was a surgery that was done by the the priests. It was usually preformed on injured warriors. During the surgery, priests would cut into a patient's skull and try to remove any bone fragments that were pressing against the brain. As deadly as this sounds, many patients survived this amazing operation.

4. Vast Empire
One of the most important achievements of the Incas was maintaining tight control over there vast empire. The Inca Empire stretched for more than 2,500 miles and perhaps 10 million people lived there. It was located in the Andes mountain range which made it hard for the Incas to get from one place to another. Yet the Incas were still able to maintain tight control over the powerful and well organized Inca empire using a large bureaucracy with many layers of authority.

5. Opposing View Point
Admittedly, some people may say that the Aztecs had the most important achievements because of there massive island city of Tenochititlan. Tenochtitlan was a great achievement because of the way the Aztecs expanded it using floating islands called chinampas. The chinampas increased the Aztecs food supply for their growing population. But the Incas come out on top because of the size of their empire and how they maintained such tight control over it using bureaucracy.

6. Conclusion
Out of all three civilizations that we studied this unit the Incas had the most important achievements. The Incas had an advanced system of roads. Secondly, they had very advanced medicine. In addition, they had a very large empire of which they kept tight control of. True, the Aztecs had a magnificent empire called Tenochtitlan but the Incas had a empire that was more advanced making them superior. As you can see the Incas had the most important achievements.