And so on. No fear of running out of topics: there is more than one a day! I am sure my commenters can come up with tons more, probably some big ones that are not coming to mind at the moment (I did not list slavery, the abolitionist movement, the civil war, Reconstruction or Lincoln since they are, in fact, covered in history class, however poorly).
"Previously, researchers had misidentified skeletons as male simply because they were buried with their swords and shields. By studying osteological signs of gender within the bones themselves, researchers discovered that approximately half of the remains were actually female warriors, given a proper burial with their weapons."