Tea is the second most consumed beverage in the world, after water. Legend has it that the Chinese Emperor Shen Nung discovered it in 2737 BC when wild tea leaves accidentally blew into his pot of boiling water. The drink became a staple of Chinese culture and was introduced to Japan by Buddhist monks in the 9th century AD. It reached Europe in the 17th century through the Dutch East India Company and became an obsession in Britain. All tea comes from a single plant species, Camellia sinensis. The differences between green, black, oolong, and white teas are determined by the degree of oxidation the leaves undergo after harvesting. Black tea is fully oxidized, while green tea is not oxidized at all, preserving its green color and polyphenols.