Chocolate was known in the ancient civilizations of Central America, particularly among the Maya and Aztec, where it was prepared as a bitter drink from cocoa beans and sometimes used as currency. After Columbus discovered the New World in the 15th century, cocoa was brought to Spain, where sugar and milk were added to make it sweet. With the Industrial Revolution in the 19th century, manufacturing methods evolved, leading to the spread of solid, modern chocolate around the world.