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the beginning of what is known as the Gangster Era, a time that roughly spans from 1919 until 1933 when Prohibition was repealed.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 National Crime Syndicate
United States President Franklin Delano Roosevelt ratified the 21st Amendment to the Constitution on December 5, 1933, repealing Prohibition. The manufacture, sale and possession of alcoholic beverages was no longer illegal and the underworld reorganized their operations to make up for the loss of profits. For years prior to the end of Prohibition, some of the most influential crime leaders from across the United States looked to organization among the gangs as the future of crime in America, leading some crime historians to believe that organized crime truly began to establish itself at a boardwalk meeting in Atlantic City, 1929.