It was at that moment one year ago that the first bombs exploded. Within minutes, a total of 10 bombs had detonated on four separate commuter trains in Madrid.
The coordinated rush-hour blasts tore through crowded compartments carrying office workers, university students, and schoolchildren. It was the bloodiest terrorist attack in Europe since the 1988 bombing of a Pan Am airliner over Scotland.
A witness struggled to describe the carnage: "It's terrible, it's true. But describing it is not comparable to seeing it."
Spain's government was quick to blame the attacks on the Basque separatist group ETA.
But evidence soon suggested the blasts were the work of militants linked to Al-Qaeda. Many saw the bombings as retaliation for Spain's role in U.S.-led military actions in Iraq and Afghanistan.
With elections just days away, then Prime Minister Jose Maria Aznar, a close Washington ally, urged voters not to throw out the government in the midst of a crisis. "We are not going to change the regime because terrorists carry out murders, nor even if they cease doing so," he said. "I say to all Spaniards, let's not aspire to anything other than the complete and total defeat of terrorism."
Aznar lost the vote, and Spain quickly pulled its troops out of Iraq.
Twenty-three bombing suspects are now in jail, most of them Moroccans. But investigators have yet to answer key questions about who organized the blasts, and how.
A parliamentary committee is due to deliver a preliminary report today on the reasons behind 11 March, and how to prevent further such attacks.
But Aznar's parliamentary bloc, still stung by last year's defeat, has refused to endorse the findings, saying they fail to explore possible ties to ETA.
There has also been little progress in European Union plans to coordinate antiterrorism efforts.
The EU appointed a central counterterrorism chief shortly after the Madrid bombings. But coordination has been slowed by bureaucratic snarls and the reluctance of some national governments to share their intelligence data.
An antiterrorism conference is being held in the Spanish capital to coincide with today's commemoration events. Spaniards also observed five minutes of silence at midday.
Radio Farda correspondent Fati Aman was in Madrid and described the mood: "I was in one of the metros. On the underground trains, people were going about their business as usual, actually. But then the music started, and the trains stopped. Things were at a standstill for five minutes. The survivors and the victims' families asked the government of Spain to let things proceed as normal [today]. But obviously, you could still see the sadness and the thinking about the victims."
Spain's King Juan Carlos and Queen Sofia also dedicated a grove of cypress and olive trees in honor of the bombing victims.