There are more people in slavery today than the total historical slave population of the America’s. The western world has ended slavery, but only in the western world. This joke is funny in Britain, it wouldn’t play in Qatar.
But you can still be practically enslaved in the US if you're a "criminal", not to mention human trafficking which also goes on here. It wouldn't be entirely right to say that it ended in the western world.
Runner up on Britain’s got talent this year