I found a good explanation into how chocolate is made on this website. I found this part particularly interesting...
"Chocolate is a general term used to describe a number of foods made from the cacao bean. It is particularly used to describe a sweet confection made from cacao with sugar added. There are many different ways to prepare it, some dating back thousands of years. It is believed that chocolate use by the Mayans dates back more than 2,500 years, and the Aztecs are also known to have used it ritually and for pleasure. This chocolate was consumed as a bitter drink, sometimes with hot peppers added, and was an important item throughout the New World."