Prohibition began in the U.S. with the passage of the National Prohibition (Volstead) Act by Congress. Sales of drinks containing more than one half of one percent of alcohol became illegal. Called a “noble experiment” by Herbert Hoover, prohibition last nearly 14 years and became highly profitable for organized crime which manufactured and sold liquor in saloons called speakeasies

Congress passed the Volstead Act providing for enforcement of the Eighteenth Amendment to the Constitution, which was ratified nine months earlier. Known as the Prohibition Amendment, it prohibited the “manufacture, sale, or transportation of intoxicating liquors” in the United States.

Source: history.com