The Great Wall of China is not a single continuous wall but a series of interconnected fortifications.
Also, it was built (and rebuilt) over a long period of time, so the sections are often different based on the engineering and military practices of each time.
If we used hovercraft instead of wheeled vehicles, we would not have to waste tens of billions every year building and maintaining roads; we would just need a few guardrails here and there to protect landscaping. And no need for spreading salt and brine to melt road ice because the hovercraft would basically treat all surfaces the same, whether lawn or snow or water it would make little difference.
Also, damage from accidents would be negligible, so insurance rates would be minimal.
Not to mention that squashed critters due to tires running over them would be a thing of the past.
So it seems like the Aztecs were ahead of their time.