It's the best known, most discussed and instantly gratifying food that few of us know anything about. For roughly 3,500 years, chocolate (or cacao, the bean from which it comes) was consumed as a drink. Then the Industrial Revolution set in, spurring the product's transformation into a more material form. Learn more about the treat you thought you knew with some fun facts. [Photo provided to China Daily] A cacao tree produces two harvests per year of 50 pods. Each pod contains about 40 almond-sized seeds – enough to make about eight bars of milk chocolate or four bars of dark chocolate. Individual cacao trees can live more than 100 years. Nathan Aztec Emperor [Illustration by Nathan Short] The Mayans and Aztecs were the first consumers of chocolate. They believed the cacao bean had magical, divine, properties appropriate for sacred rituals including birth, marriage and death. The Mayans used cacao beans as currency, while the Aztecs thought the beans more valuable than gold. More than 70% of cacao production takes place in West African countries – notably the Ivory Coast, Ghana, Nigeria and Cameroon. Around 17% comes from the Americas (mostly South America), and 9% from Asia and Oceania. Scott of the Antarctic [Photo provided to China Daily] Aztec emperor Montezuma II introduced chocolate to Spanish explorer Hernán Cortés in 1591. Montezuma II is said to have consumed 50 cups of chocolate each day for energy – and as an aphrodisiac. A cup of cocoa (using pure cacao powder) contains double the amount of antioxidants as green tea. Swiss chocolatier Rudolf Lindt invented a "conche" machine that aerated chocolate and gave it that distinct smooth, melt-in-the-mouth consistency in 1879. [Photo provided to China Daily] Roald Dahl's iconic children's book Charlie and the Chocolate Factory was inspired by the author's years in the 1930s at Repton School in South Derbyshire, England, where chocolate company Cadbury's used schoolboys as guinea pigs to taste, test and rate new products before going to market. [Photo/collectSPACE.com] Since 1981, M&M's have been an integral part of NASA's space shuttle missions, as they're included on every shuttle flight and in the agency's space-food system. Today, they feature on the International Space Station menu. [Photo/Abbie Trayler-Smith] The most valuable chocolate bar at auction was sold by Christie's in London for £470 in 2001. The more than 100-year-old-bar was taken by Captain Robert Scott on his first Antarctic expedition (1901–1904). The 10cm-long bar was made at Cadbury's Bournville factory in Birmingham, England. The cacao plant contains a bitter alkaloid compound known as theobromine, which is known to reduce high blood pressure. Aside from improving concentration and the visual processing of information, it also induces sensations of calmness, boasts anti-inflammatory properties, appeases asthma symptoms, and (in moderation) offsets everything from Alzheimer's to heart disease.