Kopi Luwak (Indonesian: coffee from [the] Luwak—Civet cat) was discovered in Indonesia under Dutch colonial rule. During that time, native farmers and plantation workers were forbidden from harvesting coffee for their own use, and were left to scrounge around for it.
Kopi luwak is the world’s most expensive coffee. The main factor of it’s high price is the uncommon method of producing such a coffee. It has been produced from the coffee beans which have been digested by a certain Indonesian cat-like animal called then palm civet or also civet cat. This is the reason kopi luwak is also called cat poop coffee or civet cat coffee. The feces of this cat will be collected, finished and sold as kopi luwak.
They soon discovered that the civet cat would eat coffee cherries and pass the seeds—the coffee beans—without digesting them (which, coincidentally, is what happens with the seeds of most fruits, and just so happens to be the evolutionary purpose of most fruits). Upon brewing coffee made from these beans, they discovered it tasted much better than the conventional coffee of the time.
There are two obvious reasons this would be the case: selective picking and thorough “washing”. The civet cat, free to graze on these cherries, would naturally consistently eat only the ripe cherries, while coffee pickers back then were much less discriminating. The beans would also have all the extra fruity bits stripped off by enzymes during digestion, resulting in a thoroughly clean result; leaving fruit pulp or mucilage on the beans can lead to fermentation or mould during drying.
You've heard the intriguingly gross stories about civet coffee (kopi luwak coffee). Coffee that's made from beans found in the poop of a cat-like animal living in an exotic location.