Chicago
The ratification of the 18th amendment to the Constitution in 1919 made the production and sale (including exportation) of alcoholic beverages illegal in the United States. This ushered in the beginning of what is known as the Gangster Era, a time that roughly spans from 1919 until 1933 when Prohibition was repealed. The 1920s saw gangsters, including Al Capone, Dion O'Banion, Bugs Moran and Tony Accardo battle law enforcement and each other on the streets of Chicago during the Prohibition era. Chicago was the location of the infamous St. Valentine's Day Massacre in 1929, when Al Capone sent men to gun down members of a rival gang, North Side, led by Bugs Moran.
Eighteenth Amendment to the United States Constitution
The Eighteenth Amendment was the product of decades of efforts by the temperance movement, which held that a ban on the sale of alcohol would ameliorate poverty and other societal issues. The Eighteenth Amendment declared the production, transport, and sale of intoxicating liquors illegal, though it did not outlaw the actual consumption of alcohol. Shortly after the amendment was ratified, Congress passed the Volstead Act to provide for the federal enforcement of Prohibition. The Volstead Act declared that liquor, wine, and beer all qualified as intoxicating liquors and were therefore prohibited. Under the terms of the Eighteenth Amendment, Prohibition began on January 17, 1920, one year after the amendment was ratified.