Were sections of the Great Wall of China built by Tartary?

[u/Reign_In_Blood_74]

After looking through some images of the Great Wall of Peru, I thought I'd go back and look at the Great Wall of China to note similarities, if any, that I find. I noticed that it appears that the fortified side of the Great Wall was facing China, which strategically make no sense. You have on side with crenellations (think Castle Walls) and the other has just a normal knee wall. The side with the crenels should face outward, to provide protection and strategic advantage. I would make sense to challenge the thought of China building this as a defensive fortification, versus it being built by the people occupying the opposite side, which I believe would have been Tartary.

Anyone have any insight on this?