Guantánamo Bay remains fully operational today, and at the moment there are 40 prisoners still held there without trial and with little prospect of release.
Last month, US President Joe Biden pledged to close Guantánamo Bay, although he can expect to face the same legal challenges and Republican opposition as Barack Obama did.
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Here’s what you need to know about The Mauritanian.
Who is Mohamedou Ould Slahi?
Mohamedou Ould Slahi is a former inmate, who was imprisoned in Guantanamo Bay for 14 years, and went on to write a memoir – Guantanamo Diary – while in captivity.
At 446 pages long, it took six years for the US government to declassify it, and it was eventually released in 2015.
His story is now the basis of the Hollywood film The Mauritanian, starring The Serpent’s Tahar Rahim as Mr Slahi and also featuring Jodie Foster and Benedict Cumberbatch.
Mr Slahi was born in Rosso, Mauritania, an Islamic republic in north-west Africa, but left as a teenager to study in Germany.
After his studies, he joined the Mujahideen – supported, finance and armed by the US – to fight against the Soviet-backed government in Afghanistan.
His second cousin, Mahfouz Ould al-Walid, became one of Osama bin Laden’s spiritual advisers, which was part of the reason he remained under the watchful eye of the authorities.
He was later interrogated after being implicated in the 9/11 terror attacks, cooperating with both Mauritanian authorities and the FBI.
Mr Slahi was then flown to Jordan where he was imprisoned for eight months, and says he was tortured there.
When he was flown to Guantánamo Bay in August 2002, he claims to have been tortured again, with methods such as being forced to drink salt water, sleep deprivation, having his family threatened and forced to stand for long periods.
Defence Attorney Nancy Hollander heard about his case and began work on it, but it was only after a lengthy legal battle that he was allowed to leave prison in 2016.
Is The Mauritanian a true story?
Mr Slahi’s story as possibly the highest-profile detainee at the infamous Guantánamo Bay camp in Cuba is now available to watch on Amazon Prime.
He was kidnapped, tortured in ways barely imaginable, and incarcerated for 14 years, but never charged with a crime.
Since his release, no western country has granted him a visa, and he was not involved in writing the film’s screenplay.
It’s had mixed reviews from critics so far.
The Mauritanian comes to Amazon Prime on 1 April.