Just browsing available domains, and the best one I could find was antislavery.com. Over 1,000,000 results in google. .com/.org/.info taken.
It's not about the money, it's about freeing the slaves! Oh, wait. Although there are some parts of the world that still have slavery, I concur with the above, unless you can find a way to monetize (and popularize) a history site about slavery.... or something.
I think you could bring in some cash with google adsense and amazon affiliate selling books. Anyways, I was also thinking on the history side, but there is also quite a bit of slavery news as well.
Amazon could be good (I don't do well with them) but I suspect Adsense will have low $/click and low CTR on that topic...... unless you focus on blonde babes kidnapped & sold into harems. Focusing on modern slavery & news items could be your best bet.