It could almost be a scene from some tale of paradise, were it not for the many tiny figures giving context to what is really happening here. A train snakes slowly across a plain in northern Mexico, the low sun casting a golden glow across the vast expanse to the mountains standing tall on the horizon. The roof of the train bears the forms of several people, moving gingerly across the tops of the wagons as they hitch a ride to the train’s destination: the US border. The natural beauty of the setting is at odds with the stark reality that has led them to undertake this journey.

Coming from the poorest regions of Mexico, Honduras, Guatemala, and as far away as Brazil, these are normal people risking their lives to reach the United States, where increased work opportunities offer a better chance of survival than remaining in their impoverished communities. For many, this is a strong enough incentive to outweigh the perils involved. Migrants are at risk from the elements, the authorities, the methods of transport, and the drug gangs who control and terrorize many of the areas through which migrants are obliged to travel. Many of those who set out to reach the US die en route, never to be seen again or, if they are found, to become just another grim statistic in the ongoing tide of illegal immigration in North and Central America.

The human cost of the gaping economic disparity which causes so many to head for the US is addressed in Who is Dayani Cristal? from British director Marc Silver and winner of the Cinematography Award for World Cinema Documentary at 2013’s Sundance Festival. Co-produced by Mexican actor Gael Garcia Bernal, the film centers on the case of the body of a young man found in Arizona. Traveling without documents, the only clue to the man’s identity was a tattoo of the words Dayani Cristal across his chest. The film uses this one example to highlight the 6,000 dead migrants found on US soil in the last decade.

There are two main threads to Who is Dayani Cristal? The first of these follows the investigation by the Medical Examiner’s Office in Tucson in documenting and identifying the body and tracing the man’s origins, while examining broader issues of how US government policy has exacerbated the problem by shutting off relatively safe passages and forcing people to attempt more dangerous routes into the country. The second narrative strand follows Garcia Bernal as he retraces the migrant journey, crossing Mexico on foot, by lorry, and on top of the aforementioned train, as he meets many of the migrants hoping to find a better life in the north.

The film’s focus on the migration passage in the Americas is one that could be replicated in different regions around the world. “It was obviously a local story to the US/Mexico border,” says Silver, “but we felt it was also a story of migration and barriers of entry that are put up around the world. We have the equivalent in Europe in the Mediterranean Sea with migrants dying travelling from North Africa to Europe. The same thing goes on, for example, between Indonesia and Australia. Even though on the surface it’s a US/Mexico story, the DNA of the film is globally relevant.”

The discovery of Dayani Cristal’s body was the first of many such instances filmed by Silver while following search and rescue teams on the US side of the border. How, as a director, did he deal with such harrowing subject matter? “I’m not interested in being detached as a filmmaker,” he says. “I respect the power of what you can do with images and I didn’t feel the need to be balanced regarding the immigration reform debate. What I thought was lacking was the humanization and the increased visibility of the subject. Most people aren’t aware that 6,000 migrants have been found dead inside the US. My role was to amplify those unheard voices along the border.”

This was achieved by tracing the route of Dayani Cristal and so many other anonymous migrants as Silver and Garcia Bernal crossed Mexico. How did the other travelers react to Garcia Bernal’s presence? “Most of them recognized him but they weren’t star-struck or anything. All we really did was ask for advice, if they could guide us and educate us across the landscape.” But is someone in Garcia Bernal’s position able to provide an accurate representation of what migrants face? “I don’t think Gael’s different to any of us,” says Silver. “Once you’ve got that sense of empathy for other humans, it doesn’t really matter what your personal situation is. We tried to craft the film so it was poetically clear that Gael was saying ‘All I can do is follow in the footsteps of this person.’ This is what we wanted to create rather than an overt reconstruction.”

One of the main contributors to Who is Dayani Cristal? is Robin Reineke, co-founder and executive director of the Colibrí Center for Human Rights which uses forensic science to identify the remains of those found in the Arizona desert. The organization has done a great deal of work in highlighting the ongoing tragedy of the nameless dead. “We’re frustrated that this continues to happen every single year,” says Reineke. “So we’re really hopeful that the film will reach a broader audience as it tells a story which is very compelling on a human level.”

In 1994, the Clinton administration adapted policies designed to reinforce the most common points of access into the US, assuming that migrants would not then risk their lives on more precarious routes. This has had little effect, serving only to expose migrants to a far higher level of danger. “From 1990 to 1999, the average number of remains found in southern Arizona was twelve (per year),” says Reineke. “From 2000 through 2013, the average was 165, a more than tenfold increase. What happens is that the parts which can be patrolled are heavily fortified, while the parts which can’t be patrolled are left open. And that’s where the migrants go. Most of these fall within Arizona and Texas.”

Since the Clinton act, the only changes have been increased militarization of frontier zones. This, according to Reineke, is absolutely the wrong strategy to be adopting towards illegal immigration. “I don’t think anything along the border is going to increase or decrease migration. Economic factors are going to have this effect. Massive structural and sociological factors are pushing people to leave their land and risk their lives crossing the border. That’s where we need to be looking in terms of solutions.”

Reineke also points out that the war on immigration does not only have a high human cost. “The loss of life is a very significant problem. The border didn’t use to be this deadly and it doesn’t have to be this way. It’s very expensive from a human rights perspective. It’s also very expensive economically. The expenditures on surveillance and walls and policing are massive. Private companies are profiting from this to a phenomenal extent. Of course, the situation is expensive to the families, and I think to us, spiritually, as a nation, but it’s also economically expensive.”

The human catastrophe that is illegal immigration to the United States ought to be at the forefront of government planning. Only then will we witness a downturn in the high numbers risking their lives to get into the country. Organizations such as Colibrí play a vital role in highlighting the situation, while films like Who is Dayani Cristal? provide a platform to bring the issue to a wider audience. Yet pressure builds from the bottom.  As Reineke says, “It’s up to us to bring this to our legislators and put the issue of loss of life along the border into the conversation on immigration reform.”

Who is Dayani Cristal? opens on April 25  in select theaters. For more info and to become active in the campaign to support migrants, visit the film’s website.