The cured leaf of Camellia sinensis is almost certainly the world's most consumed drink after water, and around it an empire, two wars, and a revolution turned. Britain's addiction to Chinese tea created a trade deficit paid first in silver, then in opium; the Opium Wars followed. British botanical espionage and new plantations in India and Ceylon — drawing on both stolen Chinese plants and indigenous Assam tea — broke China's monopoly. And in Boston in 1773, a tax on tea helped ignite an American revolution.
Tea looks like the gentlest of drinks — a leaf steeped in hot water, the kind of thing offered to someone upset. But the world's thirst for it reshaped empires. It financed colonies, triggered wars over the silver and opium used to pay for it, and helped spark a revolution. The cup of tea is one of the most consequential objects in the history of the modern world.