Answer:
Tenochtitlan was a well-established settlement of the Aztecs. It contained high-level infrastructure, a very high-level political organization, and a very rich cultural development. In other words, Tenochtitlan was a pretty sophisticated city created by a very developed society.
Step-by-step explanation:
The Aztecs were the dominating mesoamerican culture, and Tenochtitlan was their capital city. They developed it at the same pace as their society and it improved constantly, reaching its ultimate state of development and equilibrium. Reasons that lead them to conquer the rest o the mesoamerican culture and import knowledge and wealth from them, improving their society, culture, and establishments. The combination of all these factors amazed the europeans, because they realized the Mesoamericans had a very similar society to theirs.