By Robin Lustig
BBC News, Medellin
Colombia has been plagued by civil conflict for decades. Left-wing rebels continue to wage their long guerrilla war and there are still right-wing paramilitary groups, but thousands of fighters have put down their weapons and are seeking a new life.
Medellin is a safer city than its reputation suggests
I met Claudia at a school in the Colombian city of Medellin. She is 27 years old, the mother of a young child and a former guerrilla fighter.
She was wearing a purple T-shirt and jeans when we met, with her hair tightly braided. She looked, I suppose, very much like students look the world over - but her story is anything but usual.
Before I tell you Claudia's story, though, I should tell you something about Medellin.
You may have heard of it as one of the most dangerous cities in the world, the former stronghold of the notorious drugs lord Pablo Escobar.
But Pablo Escobar was shot dead by police back in 1993, and that was when the tide of violence began to turn.
Today, Medellin is a very different place.
It is a bustling city, with a population of 2.5 million and it is now said to be one of the safest cities anywhere in Latin America.
Mind you, there are still some parts of town I would not want to venture into, and even in the city centre, after dark, you do come across tight little groups of hard-eyed young men who it seems wise to steer clear of.
Back to school
But back to Claudia. The school where we met was set up especially for former fighters - they lay down their guns, come in from the jungle, and now they sit in neat rows learning to read and write.
In one classroom I peered into, they were even grappling with the arcane joys of quadratic equations.
Claudia is of mixed race - her mother came from one of Colombia's indigenous communities. She was brought up by her maternal grandfather, but he was killed by a shadowy paramilitary group - and she was left alone, shunned by her neighbours as "mestiza", mixed-race.
"I felt so alone," she told me. "I was empty inside."
So, at the age of 17, she took up arms and joined a leftist guerrilla group, persuaded by its talk of equality and the fight against poverty.
In the jungle, they taught her first aid, but it was a hard life, sleeping in the open on a plastic sheet, with commanders who expected total loyalty and total obedience.
I asked her if she had done anything she was ashamed of.
"Thanks to God," she said, "I have no blood on my hands, but I did see some things that made me question what the guerrillas said about fighting for equality."
Despite raids by the Colombian army, the drug trade continues
One day, Claudia was transferred to a base guarding a coca plantation, which her group had established to raise money for their fight.
Coca leaf is what cocaine is made from. Colombia is one of the world's major producers, and both left-wing guerrilla groups and right-wing paramilitaries are heavily involved in the drugs trade. So, Claudia decided to escape.
One night, in pouring rain, she was on guard duty. When everyone was asleep, she crept through the camp, collected up their boots and threw them away, so that her fellow fighters would not be able to chase after her.
"I was so scared," she said. "I knew that if they found me, they would kill me."
But they did not find her and now she sits in school hoping to complete her studies and then become a human rights activist, to champion the cause of Colombia's indigenous peoples.
Haunted by the past
Claudia's story is just one of thousands like hers.
Demobilisation of fighters in Colombia has proven to be controversial
More than 50,000 former fighters have now laid down their weapons, most of them former members of the paramilitary groups that are said to have had close links to the Colombian army. Men like William, who I met at the same school.
He is 37, and unlike Claudia, he does have blood on his hands. He told me he is still haunted by memories of massacres he took part in.
He cannot sleep at night, and he often goes to church when his thoughts turn to the many people he has killed.
William's biggest fear now is that his children will end up as he did - because the paramilitary are still out there, as are the leftist guerrillas.
For the past 20 years, the government has been fighting on two fronts - against the hugely powerful drugs cartels run by men like Pablo Escobar, and against the left-wing insurgents in groups like Farc, the Revolutionary Armed Forces of Colombia.
Over the years, as the fighters became traffickers, and the traffickers became fighters, it became all but impossible to tell them apart.
Now, the cartels have been smashed, but new, smaller gangs have stepped in to take their place, and they seem to be doing as much trafficking as ever - the world is still awash in Colombian cocaine. But there is less fighting.
For the people of Medellin, that is something to be thankful for. For Claudia and William, the fighting is over. But the war goes on.
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