It is approaching 200 years since the slave trade was abolished in Britain (and thereby, effectively, in the world). The Economist has an excellent analysis of the slave trade and what brought it down, comparing it to the Holocaust in the ability of the "normal" society to disregard what was going on. The campaign against slavery was remarkably successful, but depended on many factors, not least the gradual understanding that slave rebellions eventually would bring down the practice, at least in the West Indies. Once England abolished slavery, it became the chief enforcer against it.
I remember, from a business history class, another analogy to the Holocaust – the fact that most free people in the United States did not understand the suffering of the slaves because their picture of it was skewed. In terms of numbers, most of the slaves were at large farms where they were driven like cattle by forement with whips. But to most of the free population, the slaves they met were more likely house slaves – tenants and workers of small farms. These were treated better – and so the perspective of slavery was even more polarized between the slaves and the free than the judicial distinction would imply. Just like the Holocaust, the worst parts of the system were hidden from most people, who instead saw the less unacceptable side of separatism and (at least on the surface) only slightly worse conditions.
The article is interesting because it cool-headedly analyzes the slave trade and its abolishion as phenomena, and does not shrink pointing at some unwelcome facts, such as the involvement of African chiefs, or from drawing connections to the present times. Recommended.