We are all aware to varying degrees of the migrant crisis currently gripping the planet. Over 65 million people, the most since WWII, have been forced from their homes by famine, climate change and wars of choice. We sympathize, to be sure, and then turn to the sports page. Chinese artist and activist Ai Weiwei addresses that mindset by bringing a sense of scale to this world-changing calamity that’s too big to fully grasp but too heartbreaking to ignore. An art film shot by a dozen cameramen in 23 countries. A tough sit that will make you feel guilty. Guilty enough, Ai hopes, to act. (140 min)