The bitter bean of a tropical American tree (Theobroma cacao, 'food of the gods'), processed by Mesoamerican peoples into a spiced, frothy drink and used in Postclassic and contact-period Mesoamerica, by the Maya and the Aztecs, as money, tribute, and sacred substance — cacao crossed to Europe after the conquest, was sweetened into the chocolate the modern world eats, and now rests on a global cacao belt whose West African farms carry documented problems of poverty and child labor.
Among the Aztecs, you could buy things with cacao beans. A turkey hen cost about a hundred beans. A turkey egg cost three. A ripe avocado cost one. Because the beans were small, valuable, and countable, they worked as everyday money — and like any money, they were counterfeited. Forgers hollowed out the shells, removed the cacao, and packed them with mud or wax to pass as the real thing. A bean that was also a coin had to be defended against fraud. This is the strangest fact about chocolate: before it was a sweet, it was a currency, a tribute owed to emperors, and a drink fit for gods.