I remember conversations where it became apparent that people thought Chicago was a state. In everyday life, it just doesn't register to people.
Growing up in Columbus:
6th grade: we had a general social studies course
7th: Ohio history
8th: US history
9th: half World Geography/studying for Ohio standards tests
10th: can't remember...
11th: US history
12th: Democracy/Citizenship
World geography got little to attention. The 6th grade and part of 9th is total time in my public schooling is where I had the chance to learn about world religions, cultures, etc. Needless to say, those that weren't interested learn very little.
And even after the years of education I received on the topic, I know/remember very little. I don't remember all the president's names like I used to, much less remember what each did. The school system and tests they administer doesn't encourage utilization of knowledge or long-term memorization.
In math, you can't but build upon that knowledge one course after another. In these topics, you memorize, regurgitate and forget. And the US is not the only country afflicted by this system. It just so happens that the nations in Europe are smaller and are more directly affected by other nations (heck, there is an EU). It just so happens that people are much more likely to meet people of other nationalities or travel abroad, whereas I had friends in college that have never left their state!
Is a face of a man really important? I have no idea what Socrates looked like, or know even if the books attributed to him are mostly Plato's works. But that seems pretty inconsequential compared to the idea's he's credited for bring out, for the ideas he stood for, etc.