And for those Africans, slaves were a form of property, and a very valuable one. In many places, slaves were one of the only sources of private wealth because land was usually owned by the state. And this gets to a really important point. If we're going to understand the tragedy of slavery, we need to understand the economics of it. We need to get inside what Mark Twain famously called a deformed conscience. We have to see slaves both as they were, as human beings, and as they were viewed as an economic commodity. Right, so you probably know about the horrendous conditions aboard slave ships, which at their largest could hold 400 people.