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the beginning of what is known as the Gangster Era, a time that roughly spans from 1919 until 1933 when Prohibition was repealed.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.
History of the United States (1918–1945)
In 1920, the manufacture, sale, import and export of alcohol was prohibited by the Eighteenth Amendment to the United States Constitution in an attempt to alleviate high rates of alcoholism and, especially, political corruption led by saloon-based politicians. It was enforced at the federal level by the Volstead Act. Most states let the federals do the enforcing. Drinking or owning liquor was not illegal, only the manufacture or sale. National Prohibition ended in 1933, although it continued for a while in some states. Prohibition is considered by most (but not all) historians to have been a failure because organized crime was strengthened.