Assassination
Within about six months of being named prime minister, Carrero Blanco was assassinated in Madrid by four Basque members of ETA, who carried out a bombing while he returned from Mass in a Dodge 3700. Since Carrero Blanco could have become the most powerful figure in Spain upon Franco's passing, his death was perhaps instrumental in the transition toward a democratic government in that country.
In his first speech to the Cortes on 12 February 1974, Carrero Blanco's successor, the new prime minister Carlos Arias Navarro, promised liberalizing reforms including the right to form political associations. Though he was denounced by hardliners within the regime, the transition had begun.
Read more about this topic: Luis Carrero Blanco