Chocolate comes from cocoa beans, and cocoa beans come from the equatorial zones of South America. Cocoa is also grown in Africa, having been imported to that continent a long time ago. Outside of equatorial Africa and South America, the only place I know of that Cocoa is grown is in the Hawaiian Islands.

After harvesting, the beans are fermented. They are placed in large, shallow, heated trays. If the climate is right, they may simply be heated by the sun. Workers come along periodically and stir them up so that all of the beans come out equally fermented.

The first thing that commercial chocolate manufacturers do with cocoa beans is dry roast them. This develops the color and flavor of the beans to what our modern palates expect from chocolate.

Cocoa nibs, as they are called consist of two important components, cocoa solids and cocoa butter. The cocoa butter is basically fat, and the cocoa solids are essentially coarse cocoa powder. Separating the two is crucial to producing smooth, high quality chocolate candy. After all, you can't stir up crumbled up cocoa beans with some sugar, press the mixture into a bar, and call it chocolate.

There is one main process used today for getting the cocoa butter out of the cocoa solids. In the first, the cocoa nibs are converted into a non-alcoholic liquid called cocoa liquor. The liquor is then subjected to high pressure in a press to squeeze the cocoa butter from the cocoa solids. What remains is a cake of solid cocoa.

The cocoa butter is further refined for later use in chocolate production, where it is added back to the refined cocoa powder. Some cocoa butter also finds its way to the cosmetics industry.

After pressing, the cocoa solids are taken from the cocoa press and ground to a fine powder. If the cocoa powder is destined to be made into chocolate candy, it is then combined with other ingredients. Dark, bittersweet chocolates are made by adding cocoa butter and sugar, at a minimum. Milk chocolates add milk as well. Nearly all chocolates have some emulsifier to help the ingredients blend, as well as vanilla.

The ingredients are mixed under heat into molten chocolate. This goes into huge vats where it is "conched". To conch the chocolate, there are large smooth granite rollers in the vats that keep the mixture stirred and further grind the cocoa powder into extremely small bits. Some companies use smoother steel rollers which give their chocolate a very smooth, velvety feel. The longer the chocolate is conched the smoother it becomes. Good chocolates are often conched for several days straight, while cheap mass produced chocolates may be conched for as little as 12 hours.
Finally, the chocolate is poured into molds, and allowed to cool. It is then wrapped, shipped and sold for us all to enjoy.