If you're looking for especially debate-able, I'd go with some religious world event...like the birth of the Messiah, or the supposed prediction of the end of the world with the Mayan calendar.

There is always the World Wars...one event that interests me particularily in that time period was the prevalence of positive eugenics (the killing/sterilizing of the weak) before Nazism. It would be quite easy to find enough info to fill eight pages from that subject for certain. The emergence of it in America is what inspired Nazism, after all.

Hm...that's all I've got for the moment...