A five-minute primer on an issue making headlines
The capture of Italian mafia boss Bernardo Provenzano has thrown the Cosa Nostra back into the international spotlight.
We've all seen The Godfather and love The Sopranos, but where does the real mafia come from?
You have to go back about 170 years to find its origins in Sicily. What started as an extortion and protection racket in Palermo's orange and lemon farms became a secret criminal society that infiltrated the business and government elite. For decades the mafia was ignored or tolerated. Mafia comes from mafioso, which means members were 'cool' or 'beautiful'. The killings, intimidation and sordid criminal activity was explained as a peculiarly Sicilian way of looking after one's interests.
How did the mafia become so big in the United States?
It is a consequence of Italian immigration that started in the late 19th century. Initial power was concentrated - and still is - around New York, but spread to other cities. After many bloody turf wars, families like the Bonannos, Gambinos and Genovese dominated. By the mid-20th century the American mafia was reputed to have infiltrated many labour unions: the mafia built Las Vegas. There were also links with politicians, including president John F. Kennedy.
Most people's knowledge of 'the mob' is from television and films. Has that had much effect on the real thing?