As the floodwaters began to rise in the wake of the levee breaches after Hurricane Katrina, Herbert Freeman, a soft-spoken man of retirement age, insisted to his elderly, wheelchair-bound mother that they seek higher ground. When a neighbor came by with a canoe, Freeman loaded his mother in, and they paddled through the floodwaters—past dead bodies and citizens using refrigerators as makeshift rafts—trying to reach the New Orleans Convention Center, where busses were supposed to be waiting to evacuate residents. Once they arrived in the oppressive, sweltering heat, they found between 20,000 and 30,000 people already at the center, with no food, shade, drinking water, toilets, or medical facilities. Freeman flagged down a cop to try to get help for his suffering, disoriented mother, and the policeman directed him to the front of the bus line, where she would be among the first people loaded on. Freeman spent the evening assuring his mother that the buses would be there momentarily; she died in the middle of the night, sitting up in her wheelchair. When convention center workers were alerted to the dead body, they directed Freeman to leave his mother with the rest of the corpses—in a corner, outside in the heat. Four days later, the buses finally showed up.

This is the sort of movie Spike Lee's When the Levees Broke is: personal, political, infuriating, and gut wrenching. Using interviews with nearly 100 New Orleans residents and elected officials, plus countless hours of horrific footage from news sources and amateur videos, Lee expertly unfolds the tragedy of Katrina, and the far more deadly failure of the federal government to react with any urgency whatsoever. (Sri Lankan tsunami victims had food air-dropped by the US government within 48 hours. Two days after Katrina, Condoleezza Rice was smacking tennis balls around with Monica Seles, while George Bush was in San Diego, giving a stump speech about Iraq.)

When the Levees Broke is told in four one-hour acts, which is just enough time for Lee to lay out the swampy morass of negligence and horror that defined Katrina. Whatever Spike Lee's legacy may be, Levees is undoubtedly his most important film, and as a social document, it's a heart-crushing capsule of one of our country's most shameful moments.