A US jury has spared confessed al-Qaeda plotter Zacarias Moussaoui the death penalty.
The BBC's Adam Brookes in Washington looks at the background to the case.
Zacarias Moussaoui, 37, was born in Morocco and grew up in France. But it was perhaps in Britain that he began his journey into Islamic radicalism.
Zacarias Moussaoui said he knew the attack would kill Americans
He studied in London, and he worshipped at the Finsbury Park mosque.
Moussaoui seemed to embody a new generation of Islamic radicals; educated, flitting between countries, even training at al-Qaeda camps.
It was here in America, though, that his journey came to an end.
He trained as a pilot in American flight schools.
Brenda Keene, admissions officer at the Airman Flight School in Norman, Oklahoma, told the BBC: "He was a little more cantankerous than some of the other students, he was a little more pushy, a little more bossy."
At the end of his sentencing trial Moussaoui stunned the court, and America, by testifying against himself
The FBI grew suspicious and he was arrested in Minnesota in August 2001.
Moussaoui said that in his cell he rejoiced as the Twin Towers burned and collapsed. His trial began the following year.
The government argued that he knew of the 9/11 plot. Moussaoui himself claimed that he was an al-Qaeda operative, but part of a different plot.
His erratic outbursts baffled his lawyers and infuriated the judge. At times, the trial came close to collapse.
He finally pleaded guilty in 2005, but his real role in 9/11 remained unclear.
Joseph Orek, an attorney with the Open Society Policy Center, told the BBC: "Moussaoui, of course, had nothing to do with 9/11, he was in prison at the time.
"Our argument is this tenuous one that if he had told us more about what he knew while he was in prison, the US might have averted 9/11."
Moussaoui behaved erratically in court
At the end of his sentencing hearings, Moussaoui stunned the court, and America, by testifying against himself.
He had intended to fly a plane into the White House, on Osama Bin Laden's orders, he said.
And he had meant to do it together with Richard Reid, the British shoe bomber.
Was Moussaoui now seeking the death penalty, looking to secure his place as an Islamic martyr?
Zacarias Moussaoui failed as a terrorist. He was never able to carry out what he claimed were grandiose plans for an attack on the White House.
Whether he was a serious al-Qaeda operative or just a minor player has never come clear, either.
But his trial has given him a platform - and he has used it - to confuse and undermine the American criminal justice system.
In the end, Americans have a culprit, but it is much less clear whether they will have a sense of justice done for 9/11.