Salvatore "Sammy" Gravano, the highest-ranking mobster ever to break the mafia's blood oath of silence and testify against his boss, John Gotti, is considered the mafia's best-known "rat."
Tony Spilotro grew up in an Italian neighborhood on the west side of Chicago and got involved in Chicago's most powerful organized crime family, known as the "Outfit."
Frank Nitti caught his big break when Al Capone was sent to prison for tax evasion. Nitti took over and reinventing Capone's criminal empire,turning to labor units and Hollywood at after the end of Prohibition.
Leroy "Nicky" Barnes went from organizing one of the most powerful heroin rings in New York to a government informant. Barnes turned on his fellow associates and destroyed the drug trafficking empire he took so long to build.
Paul Castellano - Preview (1:55)
A preview clip from the Mobsters episode featuring James "Whitey" Bulger.
A preview of the Biography episode on the life of mobster, Roy DeMeo.
A full Biography episode on the life of mobster, Roy DeMeo.