What are some of the technological advances of the Incas and Aztecs?

The Aztecs built one of the greatest and most advanced cultural cities, Technochtitlan in Mexico! The had it on a swampy lake so it is kind of like the floating city of Venice. They also created the floating gardens called chinampas. The Incas made a very advanced road system that had to do with trading, communication, and transportation. They also built Machu Picchu and built huge stone walls.