There was one moment when making the documentary Sons of the Clouds when the director Alvaro Longoria was genuinely terrified. Wanting to take a look at the 2,700km-long Moroccan Wall that divides Morocco-held Western Sahara from the small area controlled by the Polisario Front, he - together with the film's producer and narrator Javier Bardem - was being taken to the vast sand berm in a 4x4, a trip that involved going through a minefield. Unexpectedly, the driver started veering off the tyre-tracked path.
"I've never been so scared," he says, speaking at the Berlinale in February where the film was premiered. "There are 10 million mines there and I really thought we were going to step on one. Some people have said 'you faked that' but I swear we didn't."
The wall, which Longoria says looks "unbelievable" when viewed from the sky, was one of the many things he and Bardem set out to bring to international attention with the documentary, which looks at the struggle for self-determination and "international abandonment" of the local Sahrawis - both those living under oppression in the Morocco-controlled area and those in the harsh conditions of the refugee camps on the other side of the wall that have been in existence since the 1970s.
"It's an unknown story," he says. "Really, we wanted people to know the story and to make them question why it is that our governments from the West are supporting unfair situations such as this in other parts of the world."
One of the biggest tragedies to emerge from the film is that the Sahrawi adoption of non-violent tactics has kept them away from the headlines and public attention.
"These people really believed that the rule of law would work for them and have believed in the United Nations for 25 years," says Longoria. "It's very sad to see how the international community is pushing them towards doing something to draw attention, whether it's an act of war or terror or whatever."
In the film, Bardem speaks to the renowned Sahrawi human rights activist Aminatou Haider, who has campaigned for peaceful resistance despite having spent four years blindfolded in a Moroccan prison. She describes the frustration of young Sahrawis at non-violence, especially following the very visible results of the Arab Spring, which only erupted midway through the making of the documentary.
"It's very unfortunate," says Longoria. "Unless you break something, nobody looks at you."
Arts & Life on Twitter
to keep up with all the latest news and events