Native americans in what is now mexico that settled in the valley of mexico around 1250. their empire was built across central and southern mexico. the transformed a deserted island in the middle of a lake into a major city called tenochtitlan, which becomes the hub of the empire. the aztecs build roads, bridges, and canals to carry goods to markets. they built a hug step pyramid over 150 feet high. their core religious practice was human sacrifice to the gods.