It's really sad that slavery still exists and is really prevalent, in fact there's an estimated 21 to 29 million slaves currently.
What? That's horrible!! I can't believe it! Where?
It still exists in some countries in Africa, I believe in places like Mauritania for instance.
That's very sad! I wonder why they still have slavery and why nobody does anything about it
Well, it was technically outlawed in 1981, but I think it has such a long history that people are almost accepting of it and so it continues.
I hope it will end soon. 
I do too. It's not just in Africa, though, it also exists in the USA as well, but it's better known as human trafficking and not slavery.