Modern Slavery

We talk about slavery in History class, we talk about slavery as it pertains to African Americans, but I rarely hear about the slavery that is going on in the world today. I started researching it and I am shocked that there are more slaves in the world today than at any given point in history. I guess it's a consequence of the larger population of the world today. I also found that human lives are sold for less than what they were in the past. How can we end this? Can we end this? 
Here's one article I found interesting