The Aztecs and Mayans were in North America (Mexico) the last time I looked. They were preceeded by the Toltecs of Central Mexico, the Olmecs of Caribbean coastal Mexico, and included the Zapotecs and Michtecs near Oaxaca. I have seen many of the impressive structures built by these various peoples. If by North America, you only mean the US, then consider the 50 foot high mound built at St. Louis roughly 1,000 years ago by the Mississippean culture. While perhaps the most famous and highest, there were quite a lot of others. That is why they are also known as the Mound Builders.
So, no understanding of mathematics, agriculture, domestication of animals, the wheel, the lever - their great accomplishment is that they could pile dirt.
And yes, I have been down to Mexico and have seen some Mayan ruins. The question I keep asking is 'Why did the American Indian fail so miserably to progress?' No idea of how to navigate, mine ore, build permanent dwellings, notice the stars, invent the wheel, even the most basic skills were undiscovered. No written language, no permanent dwellings; they were nomads because they had no choice but to follow the herds like any other predator.
Perhaps these huge piles were a hunting vantage point to shoot the herds from, or they ran the herds up the embankment hoping that some would fall and be able to be killed.
Why did the overwhelming majority of the American Indian fail to advance past the stone age? They had every reason to develop, harsh climate, short growing season, warfare with their neighbors. Yet, for thousands of years they did not progress; unlike the Aztecs, Mayans, Incas, Toltecs and the others. I ask a simple question ... 'Why'?