Deadly bombings that left 191 dead and 1,824 injured in Madrid were one of the worst worldwide terror attacks since the September 11, 2001 strikes on New York and Washington. In addition to the carnage, the March 11, 2004 blasts targeting the Spainish city's train network caused major psychological and political fall-out.

The country swiftly re-evaluated its contribution to U.S.-led global anti-terror operations. Three days after the attacks, blamed on Islamic militant groups including al-Qaeda, the then government was voted out of office. Its successors ended Spain's military involvement in Iraq. Meanwhile, Spain launched a massive manhunt for the perpetrators, eventually bringing 29 suspects to trial in February 2007.