The tattooed chest of a portuguese criminal who died in Lisbon circa 1880. The identity of the man is not known. The tattooed skin was removed from the body to avoid detection in dissections, as the bodies of criminals and outlaws were used for studies. Hundreds of peices of tattooed skin are preserved to this day at the Santa Maria Hospital in Lisbon.
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).