Mafia (ital. mafia) is a criminal community that formed in Sicily in the second half of the XIX century and subsequently spread its activity to large economically developed cities in the United States and some other countries. Represents an association (the so-called family) criminal groups that have a common organization, structure and code of conduct (omerta). Each group operates by carrying out racketeering (organized crime) on a certain territory — in the area of a big city, a small city or a whole region of the country.

The Mafia became the most influential group in the New York area, gradually progressing from small operations in the area of the poor Italian ghetto to influence large international organizations.

January 17, 1920, The Eighteenth Amendment to the U.S. Constitution makes it illegal to sell, manufacture or transport alcoholic beverages. Since that time, the era of "prohibition" began. Despite the fact that the law makes the sale and production of alcoholic beverages illegal, there is still a high demand for it from the public. There have been more than 900,000 cases of alcohol poisoning in American cities. Criminal gangs and politicians saw an opportunity to make a fortune and began supplying large quantities of alcohol to American cities. Most of the alcohol was imported from Canada, the Caribbean and the Midwest.

American mafiosi took advantage of the ban on alcohol and began selling it in major US cities. The profits from this far exceeded the profits from traditional crimes: concealment, extortion, gambling and prostitution. Many mafia families have made a fortune out of it. "Prohibition" contributed to the creation of mafia families in every city.