The Maya and Aztecs were the first to drink chocolate, but it was nothing like the sweet, milky version we enjoy today. Called 'xocolātl,' the ancient drink was a bitter, spicy mixture of ground cacao seeds, water, and chili peppers. It was served cold and frothed by pouring it back and forth between vessels. When the Spanish brought cacao to Europe in the 16th century, they replaced the chili with sugar and cinnamon and began serving it hot. For centuries, hot chocolate was sold in pharmacies as a medicinal drink to treat stomach ailments and low energy. It wasn't until the 19th century that cocoa powder was invented, allowing for the easy, mass-marketed instant hot chocolate we use today.