VENICE (Reuters) – Rudimentary iPhone shots of people huddled in rubber boats approaching a Greek island was what led to the creation of refugee epic “Human Flow” which Chinese artist Ai Weiwei premiered at the Venice film festival on Friday.

“I was on vacation with my son in Lesbos, we saw the boat approaching, I started using my iPhone and started shooting,” Ai told journalists ahead of the movie’s world premiere.

The phone images soon turned into a massive production involving more than 200 crew members and 23 locations: from Iraq to Bangladesh, Italy to Kenya, Afghanistan and Mexico.

Told in a way that mixes drone footage with quotes from poets and sit-down interviews, the movie does not follow one particular story but takes the viewer on a journey through the various facets of migration found in the world today.

“I have this ambition to use the film to document our time,” Ai told Reuters.

“The refugee situation has such a long history, with such political complexity and the overwhelming situation, so the use of film is the right tool for myself to study the situation and to make a historical record of our time, our moment.”

There are shots of people carrying their belongings on their backs making perilous crossings on foot or at sea, those camping in tents along barbed-wire border fences and children playing on makeshift sandy soccer fields.

In the midst of it is Ai himself, helping pull people onto the shore or comforting a veiled woman who breaks down on camera. All the while he carries his iPhone, occasionally shooting.

“If I cannot be there, if I cannot sit in the same condition with them the film will never work,” Ai said. “If I‘m not there, I have to shut up my mouth because you just don’t know it.”

The migration issue is close to Ai’s heart. The Beijing-born artist, who now lives in Berlin, was displaced when he was a child during China’s Cultural Revolution.

He already turned his attention to the refugee crisis by covering the facade of Berlin’s concert hall with 14,000 life jackets from refugees who landed on Lesbos, many of them losing their lives during the journey across the Mediterranean.

Similarly, a drone shot of thousands of abandoned life vests piled on top of each other is the closing image of “Human Flow”.

The 140-minute long documentary is Ai’s first feature-length movie and one of 21 U.S. and international movies vying for the Golden Lion that will be awarded on Sept. 9.

Putting himself in the shots not only added honesty but points to the need for activism, the dissident artist said.

“The solution is in everyone of us. If we feel that one is connected to another … then we have the solution. If we … talk about geo-politics, legislation, technical problems, then we miss the point.”