 Madrid has been one of the most targeted cities by ETA.Prior to the attack, 36 car bombs had gone off in the city in the previous 20 years and at least 119 people had been killed in attacks carried out by the armed organisation.Some of the most important attacks have been a bomb explosion inside a cafeteria on September 13, 1974, which killed 13 people, a triple bomb attack on July 29, 1979, that killed 7 people, a car bomb explosion on July 15, 1986, which killed 12 Civil Guards, as well as two car bombs that killed seven and six army members in 1993 and 1995, respectively.