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the beginning of what is known as the Gangster Era, a time that roughly spans from 1919 until 1933 when Prohibition was repealed.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.
Prohibition in the United States
However, some scholars have attributed the crime during the Prohibition era to increased urbanization, rather than to the criminalization of alcohol use. In some cities, such as New York City, crime rates decreased during the Prohibition era. Crime rates overall declined from the period of 1849 to 1951, making crime during the Prohibition period less likely to be attributed to the criminalization of alcohol itself.