50 years of ETA's violent campaign

Key events in the history of the armed Basque group ETA:

July 31, 1959 — Founded by dissident student members of the Basque Nationalist Party.

June 7, 1968 — First killing: Civil Guard Jose Pardines Arcay is shot at a checkpoint.

Dec. 20, 1973 — ETA kills the prime minister, Adm. Luis Carrero Blanco, with a bomb in Madrid.

Sept. 12, 1974 — First major attack: 12 people killed by bomb at a Madrid cafe.

1980: ETA's bloodiest year with 91 victims, nearly half of them civilians. Bloodiest attack: Car bomb in the parking lot of the Hipercor department store in Barcelona kills 21 and wounds 45.

January 1989 — Unilateral truce to help ultimately unsuccessful peace talks in Algeria.

April 19, 1995 — Failed car bomb attempt to kill conservative opposition leader and future Prime Minister Jose Maria Aznar.

July 1997 — ETA kidnaps small town politician Miguel Angel Blanco and demands the group's prisoners be brought to Basque jails. His slaying triggered widespread demonstrations in Spain.

September 1998 — ETA announces an open-ended cease-fire. It ends 14 months later after one round of talks.

March 2003 — Supreme Court outlaws radical Batasuna party linked to ETA.

March 11, 2004 — Madrid train bombings killing 191 people in an attack initially blamed on ETA but later attributed to Islamic radicals.

2004 — Police arrest more than 130 suspected ETA members, including alleged leader Mikel Antza, who is detained in France.

March 22, 2006 — ETA announces permanent cease-fire.

June 28, 2006 — Prime Minister Jose Luis Rodriguez Zapatero formally announces start of peace talks.

Dec. 30, 2006 — ETA breaks truce with a car bomb at Madrid's Barajas airport, killing two people.

May 14, 2008 — ETA kills Civil Guard officer in a car bombing outside a barracks in Basque town of Legutiano.

2009 — More than a dozen suspected ETA members arrested in France and Spain, including three alleged senior members.

June 19, 2009 — ETA kills police officer who investigated the organization.

July 29, 2009 — ETA blamed for car bombing at Civil Guard barracks in northern city of Burgos, injuring at least 46 people.

July 30, 2009 — ETA blamed for explosion on resort island of Mallorca that kills two police officers.