Aztecs: Not as primitive as they might seem

At first sight, the Aztecs might come off as primitive beings, just crawling into the age of metal working. After all they really only had writing with no real major metal working capabilities. They didn't have optics like the Europeans that came and stumbled upon the Americas. It might seem that they were inferior in every way except for many reasons as to why they weren't. For one, the huge sizes of their pyramids were something to behold. Now you might think that the Egyptians did the same thing so not very impressive right? well might think twice after learning that not only did the Aztec's not have any beasts of burden (horses, mules etc) to haul around all of this heavy stone, but they had to do it through a jungle. Another reason why they were advanced was their understanding of the cosmos. They were able to read the stars and know when certain constellations came out without a miscalculation. The Aztec were also known to build floating gardens that were so successful, they were able to harvest crops out of them at an average of 7 times a year. With that much food, its easy to see why their cities were large, and how they were able to sustain such a vast empire. Lastly, being able to build a huge city, of about 250,000 people, as their capital on top of a lake is in itself a huge task.