What, for you, are the most important areas of history to learn?

This need not only be answered by Americans, but it was central to the topic I was discussing on another forum.

What do you think are the most important areas of history for American students to study? American Revolution, WWII, Civil War, French Revolution, Enlightenment, Roman, Medieval, Latin American, etc? Either broadly or narrowly, what should history majors at American universities be learning?

I recently watched a lecture by British historian Niall Ferguson who bemoans the declining enrollment in history courses at American universities and attributes it to what he considers to be important relevant historical topics no longer being taught in favor of esoteric politically-infused topics about gender and race and other factors in history.

So then what should be taught? I was not a history major. I took only three history courses in college, mostly out of curiosity: History of the Crusades, Early Civilizations (Sumerian, Harappan, etc.) and Roman History (Republic to 2nd century AD).