This is my attempt to explain this.
The US is a very interesting place.
Its history is interesting.
Its geography is interesting.
Its culture is interesting.
In each case, the word Its is a determiner. That means it is introducing one specific feature possessed by the United States. Because there are several features in my mind, I make reference to which feature I mean by using a reference word. I could also use The in place of Its to do effectively the same determining job.
I could also phrase the same thought in a similar way.
The history (of the US) is interesting.
The geography (of the US) is interesting.
The culture (of the US) is interesting.
The only difference is that here the particular place (US) is included within the phrase itself where before it was mentioned previously.
Now, with a completely different focus of meaning, compare:
The history of the US is interesting.
The history of England is interesting.
The history of Thailand is interesting.
With this contrast I mean to show that the focus here is not on history (as opposed to geography or culture) but on the US (as opposed to England or Thailand).
So if I understand correctly, Mike MC is very reasonably wondering why it is necessary to use a determining The in this thought. We can't use the same explanation as before. What is the need to make reference here? Well, my answer is that now we don't absolutely completely 100% have to.
History (of the US) is interesting.
History (of England) is interesting.
History (of Thailand) is interesting.
Now I'm not saying that the above are natural at all but I am saying that they are barely just about acceptable on a conceptual level, and the reason why they may not sound right is that there is a better, more economical way of expressing the focus of this thought:
US history is interesting.
English history is interesting.
Thai history is interesting.
Here, the sense is clear. The determinative US is specifying which country I'm talking about, not which feature of the country.