Habi Mint Rabah was born a slave. She tells her story calmly, without self-pity: how her mother was kidnapped by slave traders; how she was separated from her family and forced to work in the kitchen of her "master," who beat her and raped her. It all seemed so normal that she never questioned it.
"I carried the water on my back," she says. "I ate the leftover food. If they left nothing, I had nothing to eat. I was sleeping wherever I could find a place – sometimes in the sand, with the goats."
She shows little emotion until she remembers one detail. As a faithful Muslim, she had to ask for permission to pray. Tears spring to her eyes as she remembers her master telling her that she did not deserve to, because her soul was inferior.
"You are only here to work," he told her. And so she never prayed, and felt overwhelming guilt.
Ms. Rabah's story is shockingly common. At least 21 million people worldwide are kept in slavery or forced labour, according to the International Labour Organization (ILO). Some estimates put the number as high as 36 million. Many are in debt bondage, or in forced servile marriages, or trafficked for sexual exploitation, or in unpaid labour as migrants on construction sites.
Despite frequent global pledges to eradicate slavery, the practice still exists in many countries and workplaces, from brothels and farms to kitchens and factories. (India, Pakistan, China and Uzbekistan have some of the largest slave populations in the world.) Labour provided by slaves generates $150-billion (U.S.) in annual profits for the ruthless businesses that control their lives, according to ILO studies.
While slavery is a global scourge, it is here in the former French colony of Mauritania where it's most prevalant: About 4 per cent of Mauritania's population – about 150,000 people – are believed to be held in slavery today. "Slaves are seen as objects, or animals, not as people," says Balla Touré, an anti-slavery activist here.
This small nation in the harsh desert of West Africa is dominated by the "White Moors" – an Arab-Berber minority who control the economy, the government and most of society. Members of a darker-skinned caste, the Haratin (also sometimes called "Black Moors"), have been enslaved as cattle herders or domestic labourers for centuries. Historically treated as chattel, they inherited their status, and many are still enslaved.
Mauritania was the last country in the world to abolish slavery officially. That was in 1981. Yet the practice continued, and Mauritania did not criminalize it until 2007. Since then, dozens of slavery cases have been reported to police, but Amnesty International has found that only one slave-owner has ever been convicted, in 2011. He was released on bail within a few months, pending his appeal, which has yet to take place.
Mauritania's government routinely denies that slavery exists here. Only a few "vestiges" remain, it says.
Even after the government passed stronger legislation last year, calling slavery a "crime against humanity," the police and courts have refused to enforce it. Indeed, the government shows much more vigour in prosecuting anti-slavery activists than it has ever shown in prosecuting slave owners. It claims that the activists are stirring up "ethnic divisions."
Speak up – and go to jail
Boubacar Messaoud, a former slave who became one of the country's most prominent anti-slavery campaigners, has lost track of how many times he has been arrested by the authorities for his activism – at least five or six, he says, including once when he was imprisoned for more than three months.
Jail is still used as a weapon against the anti-slavery movement. Mauritania's most famous campaigner, Biram Dah Abeid, and one of his comrades, Brahim Bilal, are currently in the second year of a two-year prison sentence. They were arrested while leading a peaceful protest in a convoy of cars driving across a rural district. Another activist, Mr. Touré, has been arrested several times and once spent 40 days in prison.
Their organization, the Initiative for the Resurgence of the Abolitionist Movement (IRA), is considered illegal, and the authorities have closed and padlocked its offices in Nouakchott, the capital city. Diagonal black lines have been painted across its walls to warn away anyone who seeks its help.
"We're used to this pressure," Mr. Touré shrugs. "It's normal. We were a little scared in the past, but now we don't care."
Many of the anti-slavery activists are themselves the descendants of slaves, although they have been joined by a few members of the Arab-Berber group and other minorities. Mr. Touré grew up with many Haratin friends and was shocked to see the treatment of the Haratin when he travelled around Mauritania for his job as an agricultural consultant. He visited small oasis towns in the desert where a single Arab-Berber landowner would control all the land, while a hundred Haratin residents would need his permission to get water to drink. It angered him so much that it spurred him into activism.
Mr. Messaoud works with another group, SOS Slaves, and describes Mauritania as an essentially feudal society, dominated by an Arab-Berber elite. Mauritanian religious leaders have often followed a series of ancient Islamic interpretive texts, written from the eighth to 14th centuries, which legitimize the practice of slavery.
Most judges in the country belong to this elite, and many have been influenced by the ancient texts, which anti-slavery activists maintain are illegitimate and outdated. Some even possess slaves, so they are reluctant to take action, Mr. Messaoud says.
The elite's wealth, too, depends on the unpaid labour of their slaves. Although there are vast mineral resources buried in its desert sands, Mauritania is one of the world's least-developed and most unequal countries, ranking 161st of the 187 countries on the UN's human-development index.
While the urban elite are affluent, most of the population lives in poverty, and hunger is widespread among the rural poor. The government is authoritarian and military-dominated, following a 2008 coup and subsequent stage-managed elections. But it benefits from Western military support because it is seen as a reliable bulwark against Islamist radical groups in neighbouring countries.
What is most disturbing, Mr. Messaoud says, is the psychology of slavery that persists across the entire society, including among slaves themselves. Inculcated with such traditional beliefs as seeing slavery as God's will, they often refuse to leave their "masters" when outsiders try to rescue them. Barred from attending school, usually illiterate, and isolated from society, they know no other life than slavery and often find it shameful to leave their master's household. Some insist on getting a police document to "prove" that they can leave. "Even the slaves deny the existence of their own slavery, because they don't want to alienate themselves from their master's family," Mr. Messaoud said in an interview in Nouakchott.
"This a profoundly unequal society, like many African and Arab societies. The authorities refuse to recognize slavery still exists. They use Islamic texts to justify their slavery, just as the United States used Christianity to justify slavery in the 19th century."
Criticism 'out of proportion'
Some activists, led by Mr. Abeid, have turned to direct confrontation – protest rallies, hunger strikes, attempts to rescue slaves, even the public burning of traditional religious texts that justify slavery – because of their impatience with the government's complacency.
Despite the laws and promises, there is no sign of urgency among the governing elite. One senior official, speaking on condition of anonymity because he was unauthorized to give interviews, insisted that the criticism of slavery is "out of proportion." The issue can be "solved through dialogue," he said.
Asked why Mr. Abeid was imprisoned, he replied: "His fight is right, but his methods are wrong. He is pouring oil on the fire of ethnic divisions."
The government's promise of "dialogue" is an empty one, the activists say. If dialogue were possible, they ask, why are the police arresting people at peaceful anti-slavery protests, while ignoring cases of slavery that are brought to their attention?
Mr. Touré recalls a sympathetic police chief who agreed to investigate a slave-owner. The owner claimed the enslaved woman was his sister, but the police chief knew that to be false. He had the man taken into custody for two days – but then the slave-owner disappeared from his locked cell during the night, clearly with the support of local authorities.
From servitude to poverty
One of the slaves helped by Mr. Touré's organization is a woman named Mbarka Mint Essatim who, like many former slaves, now lives in poverty, in a slum on the edge of Nouakchott inhabited by the Haratin.
She and her children occupy a one-room hut with wooden slats for walls and a tin roof, along with goats wandering the dusty ground outside.
A shy and quiet 27-year-old with a perpetually downward gaze, Ms. Essatim was freed about four years ago, but still struggles with slavery's legacy of poverty and oppression.
Born into a slave family, she was separated from her mother at a young age and taken into the household of a wealthy Arab-Berber businessman. As a child, she thought she was part of the master's family – but she was ordered to eat alone. Then she was forced into domestic servitude.
She herded goats and cows, scrubbed floors and washed dishes. She slept outside the house and never went to school. If she didn't work fast enough, the slave-owner's sisters beat her with electrical cables, leaving scars that are still visible.
Once she dared to tell them that she was too sick to sweep the house, but they refused to let her stop working. She never protested again. "They were very cruel to me," she says. "I was very afraid of them."
She says she was raped repeatedly by the slave-owner and became pregnant with his child at 14. Later she was raped by the slave-owner's son and became pregnant with a second child.
Eventually the master's chauffeur befriended her, felt sorry for her plight, and helped her escape. They married, but the slave-owners refused to let her have her two children. So with the help of the anti-slavery activists, she went to court to demand their return.
It was a courageous confrontation with the system, and became a landmark case in Mauritania. Challenging a slave-owner in court was considered so radical that her own mother became enraged and took the side of the slave-owners, calling her "unfit" to have her children. The judge pressured her to drop the case. But she persisted and eventually won custody.
"My liberty is still not complete," Ms. Essatim says. "I have no proper house, no education for my children. I still have questions about what happened to me. I don't understand why I was in slavery. Why was I raised by white people, not by my mother? I ask myself these questions all the time."
But her victory in 2013 was a sign that the times are changing.
"There is progress, because now the Haratin know their rights," Mr. Messaoud said. "Haratin isn't a pejorative word any more. They're proud of being Haratin.
"In the past, they were tied to their masters, but now they are trying to be more independent. I'm sure that this awakening is because of our fight."
Rescued in spite of herself
Habi Mint Rabah, the woman prohibited from praying, was finally freed by her brother, Bilal. He was a slave, too, forced to work as a camel herder, until he ran away at 19 after his master had whipped him with the camel ropes.
His mother, indoctrinated into slavery, opposed his plan to escape. "If you run away, I'll never forgive you," she told him. But when he threatened suicide, she let him go.
Bilal later returned and persuaded the owner to free his mother. He rescued a younger sister and brother, and finally found Ms. Rabah in a slave-owner's tent in the desert. With the help of the activists, he was able to free his sister. Video of the rescue shows her unwilling to leave, and briefly even denying her slavery.
Ms. Rabah, now 42, lives on the outskirts of Nouakchott in a Haratin slum called Tarhil – the "place of the displaced" – where she makes a meagre living by selling vegetables and tea from a small stand.
"Even if sometimes I don't have anything to eat, at least I have my freedom now," she says.
"My freedom is the most important thing. I'm like another person now. I'm the master of my own life."
Her 10-year-old son is attending school – a privilege denied to his mother and countless generations of slaves. "He's the best in his class," she says proudly.
"I'm so happy to see my son in school, with a promising future. I'm so happy, I can't even put it in words."
Mr. Abeid, the leading anti-slavery activist, has been transferred to a remote prison where visitors have less access to him. But in letters, he has vowed to continue his fight, telling his supporters: "I refuse to be silenced."
Geoffrey York is The Globe and Mail's correspondent in Africa.