While Europe still grapples with immigration, this is only a small part of a growing global refugee crisis. Millions leave their homes, be the reason decaying environment, war, poverty or just the promising call of a better life elsewhere. Ai Weiwei, one of the most vocal dissidents in China, itself the frontrunner of instate migration, and a superstar of modern art, paints an epic yet thoughtful picture of the vast human flow. To make this overarching and truly global film, the crew travelled through 23 countries.