The chocolate industry is worth an estimated $110 billion a year, and yet its key commodity is grown by some of the poorest people on the planet, in plantations that can hide the worst forms of child labor.

Two years ago CNN uncovered slavery in the plantations of Ivory Coast. Now manufacturers are facing up to the growing demand for "ethical" chocolate and are taking measures to clean up their supply chains.

But do these measures go far enough and are they fast enough? In the forthcoming series airing on CNN International from February 27, CNN returns to Ivory Coast. Ahead of that, you can read more background about how slavery has tainted the industry. You can find out where in the world the demand for and supply of chocolate is greatest, look at the true cost of a bar of chocolate and see how it is made from bean to bar by scrolling through our info-graphics.

You can also take part in our iReport challenge to eat ethically, and you can meet the village elder who gets to taste a KitKat for the first time.