It seems ridiculous, not to mention unfair, to review Ai Weiwei's epic Human Flow in abbreviated form. But faced with the choice of ignoring Ai's movie during a busy week or calling attention to it -- even in meager fashion -- I decided to choose the latter course. An artist with an international reputation, Ai takes a sweeping, often heart-breaking look at the throngs of people who, through no fault of their own, have been dislocated. Making use of drone shots and of more intimate earth-bound footage, Ai condenses a year's worth of filming into two hours and 20 minutes, occasionally appearing in the movie to console those who are suffering. (I didn't see Ai's on-camera stints -- though brief -- as necessary.) Ai and his crew capture so many memorable images that it becomes nearly impossible to sort through them. A group of refugees crosses a turbulent river only to face a terrible obstacle, a barbed wire fence at the Greek/Macedonian border. Exhausted refugees are picked out of boats by rescue workers. Muddy refugee camps look dauntingly bleak. Ai isn't afraid to let his images speak for themselves, but he also puts bits of information on the screen and adds interviews. We meet Syrian refugees, as well as refugees from Kenya, Bangladesh, Afghanistan, and Gaza. We travel with Ai along the U.S.-Mexican order. The film makes you realize how violence has caused massive movements of people across the surface of our battered planet. In all, Ai visited 23 countries, and he exposes the kind of suffering that comes from losing one's place -- both geographically and culturally. An overhead shot of refugees in Turkey makes people look like microbes; it's as if we're observing life on Earth from the perspective of aliens and wondering about the conditions that have forced more than 65 million people from their homes since the end of World War II. The movie's title includes the word "human." And Ai leaves us with a question he doesn't have to state: If we wish to call ourselves human in any meaningful way, how can we ignore what we've seen?