The Kray Twins, Ronnie and Reggie Kray, were notorious British gangsters active in London during the 1950s and 1960s. They led the Kray Firm, a criminal organization involved in various illegal activities, including extortion, robbery, and murder. The twins were known for their violent behavior and charismatic personalities, which helped them gain influence in the underworld. The Kray Twins became infamous not only for their criminal exploits but also for their connections to celebrities and the London social scene. Their reign ended when they were arrested in 1968 and subsequently sentenced to life in prison for murder. Their story has been depicted in various films and books, highlighting their complex legacy.