A couple holds hands as they look at the image of a young couple who were killed in the Madrid train bombings at the "Forest of the Remembrance" (El Bosque del Recuerdo), a memorial garden which commemorates the victims of the 2004 Madrid train bombings, in Madrid March 11, 2015. The Spanish capital on Wednesday marked the eleventh anniversary of the Madrid train bombings that killed 191 people and injured more than 1,500. The white flowers hanging from the trees are placed on the trees for each victim of the bombings. REUTERS/Susana Vera (SPAIN - Tags: DISASTER TRANSPORT SOCIETY ANNIVERSARY) 

People build human towers called Muixeranga at the Plaza de la Virgen (Virgin Square) during a a protest in memory for those who died in a 2006 subway train accident in Valencia, July 3, 2014. Some 43 people died and 47 people were injured in the second worst train accident in Spanish history on July 3, 2006. The Association of Victims of the Accident (AVM3J) obtained the opening of a new investigation after a TV programme made public new facts about a lack of maintenance in the subway network in April 2013. REUTERS/Heino Kalis (SPAIN - Tags: SOCIETY POLITICS ANNIVERSARY) 

A woman visits the interior of the Madrid train bombing memorial at Atocha station, in Madrid March 11, 2014. The Spanish capital on Tuesday marked the tenth anniversary of the Madrid train bombings that killed 191 people and injured more than 1,500. REUTERS/Susana Vera (SPAIN - Tags: TRANSPORT ANNIVERSARY DISASTER TPX IMAGES OF THE DAY) 

A bouquet of flowers lies on the railway tracks at Madrid's Atocha station March 11, 2014. The Spanish capital on Tuesday marked the tenth anniversary of the Madrid train bombings that killed 191 people and injured more than 1,500. REUTERS/Susana Vera (SPAIN - Tags: TRANSPORT DISASTER ANNIVERSARY) 

The picture of a young woman is seen at a memorial site for the victims of the March 11 train bombings at the same spot where a train was bombed ten years ago outside Madrid's Atocha station March 11, 2014. The Spanish capital marked on Tuesday the tenth anniversary of the Madrid train bombings that killed191 people and injured more than 1,500. REUTERS/Susana Vera (SPAIN - Tags: CIVIL UNREST ANNIVERSARY TPX IMAGES OF THE DAY) 

People walk past a monument dedicated to the Madrid train blast victims at El Pozo station, outside Madrid March 11, 2011. The Spanish capital marked on Wednesday the seventh anniversary of the Madrid train bombings that killed 191 people and injured more than 1500. REUTERS/Juan Medina (SPAIN - Tags: CIVIL UNREST DISASTER ANNIVERSARY) 

A man visits the interior of the Madrid train bombing memorial outside Atocha station during the sixth anniversary of the attacks in central Madrid March 11, 2008.The Spanish capital marks today the sixth anniversary of the Madrid train bombings that killed 191 people and injured more than 1500 in Europe's deadliest Islamist attack.REUTERS/Susana Vera (SPAIN CONFLICT - Tags: CIVIL UNREST ANNIVERSARY) 

People visit the interior of the Madrid train bombing memorial outside Atocha station during the sixth anniversary of the attacks in central Madrid March 11, 2008.The Spanish capital marks on Thursday the sixth anniversary of the Madrid train bombings that killed 191 people and injured more than 1500 in Europe's deadliest Islamist attack.REUTERS/Susana Vera (SPAIN CONFLICT - Tags: CIVIL UNREST ANNIVERSARY) 

A relative of a victim of the 2004 train bombings gets overcome by emotion during a gathering of the "Asociacion 11-M Afectados del Terrorismo" (March 11-Victims of Terrorism Association) outside Madrid's Atocha station March 11, 2010. The Spanish capital marks today the sixth anniversary of the Madrid train bombings that killed 191 people and injured more than 1500 in Europe's deadliest Islamist attack. REUTERS/Susana Vera (SPAIN CONFLICT - Tags: CIVIL UNREST ANNIVERSARY IMAGES OF THE DAY) 

Pilar Manjon (2nd L), president of the March 11-Victims of Terrorism Association, embraces the relative of a victim during a gathering outside Madrid's Atocha station March 11, 2009. The Spanish capital marked on Wednesday the fifth anniversary of the Madrid train bombings that killed 191 people and injured more than 1,500. REUTERS/Susana Vera (SPAIN ANNIVERSARY SOCIETY) 

(L-R): Madrid's deputy mayor Manuel Cobo, Socialist spokesman at Madrid's city hall David Lucas, Izquierda Unida spokesman at Madrid's city hall Angel Perez, Spanish Minister of Development Magdalena Alvarez and Madrid's mayor Alberto Ruiz Gallardon observe five minutes of silence during a ceremony inside the Madrid train bombing memorial at Madrid's Atocha station March 11, 2009. The Spanish capital marks today the fifth anniversary of the Madrid train bombings that killed 191 people and injured more than 1500. REUTERS/Susana Vera(SPAIN ANNIVERSARY CONFLICT SOCIETY IMAGE OF THE DAY TOP PICTURE) 

A bouquet of flowers bearing the phrase, "We remember you" hangs at Madrid's Atocha station March 11, 2009. The Spanish capital marks on Wednesday the fifth anniversary of the Madrid train bombings that killed 191 people and injured more than 1500 in Europe's deadliest Islamist attack. REUTERS/Susana Vera (SPAIN ANNIVERSARY CONFLICT) 

Women visit the interior of the Madrid train bombing memorial outside Atocha station during the fourth anniversary of the attacks in central Madrid March 11, 2008. REUTERS/Susana Vera (SPAIN) 

The head of a victims association, Pilar Manjon, speaks to reporters outside the High Court after hearing the verdicts of the 2004 Madrid train bombings trial in Madrid October 31, 2007. A Spanish judge on Wednesday found 21 people guilty of involvement in the bombings, Europe's deadliest al Qaeda inspired attack, which killed 191 people and injured 1,800. REUTERS/Susana Vera (SPAIN) 

Some of the 28 suspects accused of the 2004 Madrid train bombings (L-R) Jamal Zougam, Rachid Aglif, Rafa Zouhier y Abdelilah El Fadual are seen sitting in court inside an annex of High Court in Madrid, October 31, 2007. The court will deliver verdicts on Wednesday, ending a politically charged trial into Europe's deadliest al Qaeda inspired attack which killed 191 people and and injured more than 1,800. Best quality available. REUTERS/Paco Campos/Pool (SPAIN) 

Commuters walk to catch a train at Atocha station in Madrid October 30, 2007. A Spanish court will hand down verdicts on 28 people accused of playing a role in the 2004 Madrid train bombings on Wednesday, ending a politically-charged trial into Europe's deadliest al-Qaeda related attack. REUTERS/Susana Vera (SPAIN) 

A commuter smokes before catching a train at Atocha station in Madrid October 30, 2007. A Spanish court will hand down verdicts on 28 people accused of playing a role in the 2004 Madrid train bombings on Wednesday, ending a politically-charged trial into Europe's deadliest al-Qaeda related attack. REUTERS/Susana Vera (SPAIN) 

Commuters walk to catch a train at Atocha station in Madrid October 30, 2007. A Spanish court will hand down verdicts on 28 people accused of playing a role in the 2004 Madrid train bombings on Wednesday, ending a politically-charged trial into Europe's deadliest al-Qaeda related attack. REUTERS/Susana Vera (SPAIN) 

Commuters wait to catch a train at Atocha station in Madrid October 30, 2007. A Spanish court will hand down verdicts on 28 people accused of playing a role in the 2004 Madrid train bombings on Wednesday, ending a politically-charged trial into Europe's deadliest al-Qaeda related attack. REUTERS/Susana Vera (SPAIN) 

Commuters wait for their train to leave Atocha station in Madrid October 30, 2007. A Spanish court will hand down verdicts on 28 people accused of playing a role in the 2004 Madrid train bombings on Wednesday, ending a politically-charged trial into Europe's deadliest al-Qaeda related attack. REUTERS/Susana Vera (SPAIN) 

Commuters walk to catch a train at Atocha station in Madrid October 30, 2007. A Spanish court will hand down verdicts on 28 people accused of playing a role in the 2004 Madrid train bombings on Wednesday, ending a politically-charged trial into Europe's deadliest al-Qaeda related attack. REUTERS/Susana Vera (SPAIN) 

A man visits the Madrid train bombing memorial at Atocha station in Madrid October 30, 2007. A Spanish court will hand down verdicts on 28 people accused of playing a role in the 2004 Madrid train bombings on Wednesday, ending a politically-charged trial into Europe's deadliest al-Qaeda related attack. REUTERS/Susana Vera (SPAIN) 

Some of the accused in the 2004 Madrid train bombings sit in court in this video frame grab taken inside an annex of the High Court in Madrid March 13, 2007. The trial of 29 suspects in the 2004 Madrid attacks continued two days after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Jamal Zougam (R), one of the accused in the 2004 Madrid train bombings, sits in court with Abdelmajid Bouchar in this video frame grab taken inside an annex of the High Court in Madrid March 13, 2007. The trial of 29 suspects in the 2004 Madrid attacks continued two days after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Mohamed Larbi Ben Sellam, one of the accused in the 2004 Madrid train bombings, sits in court in this video frame grab taken inside an annex of the High Court in Madrid March 13, 2007. The trial of 29 suspects in the 2004 Madrid attacks continued two days after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Abdelmajid Bouchar, one of the accused in the 2004 Madrid train bombings, sits in court in this video frame grab taken inside an annex of the High Court in Madrid March 13, 2007. The trial of 29 suspects in the 2004 Madrid attacks continued two days after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Abdelmajid Bouchar (L), one of the accused in the 2004 Madrid train bombings, sits in court with Mohamed Larbi Ben Sellam (R) in this video frame grab taken inside an annex of the High Court in Madrid March 13, 2007. The trial of 29 suspects in the 2004 Madrid attacks continued two days after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Mouhannad Almallah Dabas, one of the accused in the 2004 Madrid train bombings, listens to a protected witness testify in this video frame grab taken inside an annex of the High Court in Madrid March 12, 2007. The trial of 29 suspects in the 2004 Madrid attacks resumed a day after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Mouhannad Almallah Dabas (R), one of the accused in the 2004 Madrid train bombings, smiles as he sits near some of the other accused including Hamid Ahmidan (C) and Othman El Gnaoui (L) in this video frame grab taken inside an annex of the High Court in Madrid March 12, 2007. The trial of 29 suspects in the 2004 Madrid attacks resumed a day after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Mouhannad Almallah Dabas (C), one of the accused in the 2004 Madrid train bombings, sits in court with others in this video frame grab taken inside an annex of the High Court in Madrid March 12, 2007. The trial of 29 suspects in the 2004 Madrid attacks resumed a day after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Abdelilah El Fadual (L), Rachid Aglif and Mohamed Bouharrat (R front), some of the accused in the 2004 Madrid train bombings, sit in court in this video frame grab taken inside an annex of the High Court in Madrid March 12, 2007. The trial of 29 suspects in the 2004 Madrid attacks resumed a day after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Mouhannad Almallah Dabas, one of the accused in the 2004 Madrid train bombings, sits in court in this video frame grab taken inside an annex of the High Court in Madrid March 12, 2007. The trial of 29 suspects in the 2004 Madrid attacks resumed a day after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Hamid Ahmidan (C) yawns as he is flanked by Othman El Gnaoui (L) and Mouhannad Almallah Dabas (R) along with other of the accused in the 2004 Madrid train bombings in this video frame grab taken inside an annex of the High Court in Madrid March 12, 2007. The trial of 29 suspects in the 2004 Madrid attacks resumed a day after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Rabei Osman Sayed Ahmed "Mohamed the Egyptian" (L), Abdelilah El Fadual (2nd L), Rachid Aglif and Mohamed Bouharrat (front R), some of the accused in the 2004 Madrid train bombings, sit in court in this video frame grab taken inside an annex of the High Court in Madrid March 12, 2007. The trial of 29 suspects in the 2004 Madrid attacks resumed a day after the three-year anniversary of the massacre that killed 191 people and wounded more than 1,800 rush hour commuters. REUTERS/Pool (SPAIN) 

Javier Gonzalez Diaz, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Javier Gonzalez Diaz, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Ivan Reis, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Ivan Reis, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Sergio Alvarez Sanchez, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Sergio Alvarez Sanchez, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Ivan Granados Pena, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Ivan Granados Pena, one of the accused in the 2004 Madrid train bombings, sits in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Emilio Llano Alvarez, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Raul Gonzalez Pelaez, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Raul Gonzalez Pelaez, one of the accused in the 2004 Madrid train bombings, speaks in court in this video grab taken inside an annex of the High Court in Madrid March 1, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its ninth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Raul Gonzalez Pelaez, one of the accused in the 2004 Madrid train bombings, sits in court in this video grab taken inside an annex of the High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Carmen Toro Castro, one of the accused in the 2004 Madrid train bombings, speaks in court in this video frame grab taken inside an annex of the High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Carmen Toro Castro, one of the accused in the 2004 Madrid train bombings, speaks in court in this video frame grab taken inside an annex of the High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Carmen Toro Castro, one of the accused in the 2004 Madrid train bombings, listens in court in this video frame grab taken inside an annex of High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Antonio Toro Castro, one of the accused in the 2004 Madrid train bombings, gestures as he speaks in court in this video frame grab taken inside an annex of High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Antonio Toro Castro, one of the accused in the 2004 Madrid train bombings, speaks in court in this video frame grab taken inside an annex of High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Jamal Zougam (L) and Fouad el Morabit el Amghar, accused in the 2004 Madrid train bombings, listen in court in this video frame grab taken inside an annex of High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Jamal Zougam, one of the accused in the 2004 Madrid train bombings, listens in court in this video frame grab taken inside an annex of High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Rabei Osman Sayed Ahmed "Mohamed the Egyptian" (L), one of the accused in the 2004 Madrid train bombings, listens along with other accused, in court in this video frame grab taken inside an annex of High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Jose Emilio Suarez Trashorras, one of the accused in the 2004 Madrid train bombings, speaks in court in this video frame grab taken inside an annex of High Court in Madrid February 28, 2007. The trial of 29 suspects in the bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Jose Emilio Suarez Trashorras, one of the accused in the 2004 Madrid train bombings, speaks in court in this video frame grab taken inside an annex of High Court in Madrid February 28, 2007. The trial of 29 suspects in the 2004 Madrid train bombings began its eighth day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Jose Emilio Suarez Trashorras, one of the accused in the 2004 Madrid train bombings, speaks in court in this video frame grab taken inside an annex of High Court in Madrid February 27, 2007. The trial of 29 suspects in the 2004 Madrid terrorist attacks began its seventh day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN) 

Jose Emilio Suarez Trashorras, one of the accused in the 2004 Madrid train bombings, testifies in court in this video frame grab taken inside an annex of High Court in Madrid February 27, 2007. The trial of 29 suspects in the 2004 Madrid terrorist attacks began its seventh day under tight security, with survivors and mourners getting a close-up look at the defendants accused of a massacre that killed 191 people and wounded more than 1,800 rush hour commuters nearly three years ago. REUTERS/Pool (SPAIN)