The only time I was ever taught about ancient greece, egypt, china, etc was in third grade, and I hardly think that counts. I've gone to school in three different states, so I have at least some reasonable sample of nation, and although there is no national curriculum, the curricula are generally similar enough.
And college history courses assume that you already have enough knowledge from high school history courses to understand the historical context of what they teach, but by teaching American history separate (and before) world history, we are not taught any global context for events in American History.
And college history courses assume that you already have enough knowledge from high school history courses to understand the historical context of what they teach, but by teaching American history separate (and before) world history, we are not taught any global context for events in American History.