Oscar-winning documentarian Steven Okazaki goes well beyond the hard facts and cold figures in White Light/Black Rain, a comprehensive look at the two nuclear explosions that ended World War II (the Japanese surrendered a few days after the bombing of Nagasaki) and the aftermath that continues to this day.

Okazaki structures White Light/Black Rain for maximum impact, beginning with newsreel footage of the Japanese attack on Pearl Harbor and other events leading up to July 16, 1945, when the first atomic bomb was tested. He then shows street scenes of modern-day Hiroshima, which now looks more or less like any other Japanese city, then interviews young people on the street, all of whom are clueless about what happen on August 6, 1945.

From there, much of the story is told through interviews with survivors of the explosions, like Kiyoko Imori, who was three blocks from Ground Zero in Hiroshima and somehow wasn’t incinerated, even though her family and classmates were killed (she tearfully states her belief that she was spared so she could “tell people what happened, so they’ll understand”); Keiji Nakazawa, whose experiences were turned first into a series of graphic novels (Barefoot Gen), which was later as a pair of animated movies; and a doctor who viewed the explosion over Nagasaki and notes that the mushroom cloud was actually “a pillar of fire.”

Some survivors have physical scars; one woman has facial burns and gnarled hands, while a man had flesh fused to bone on his chest (“You can see my heart beating between the ribs”). All of the survivors have emotional scars, having watched their families, city and way of life taken from them in a literal flash. “My siblings never got to try chocolate, and the other wonderful things of life,” one survivor laments.

There are also interviews with Americans who helped build and deliver the bombs. They express surprise at how powerful the bombs, dubbed “Little Boy” and “Fat Man,” really were—one points out that anyone suggesting dropping a nuclear bomb on Iraq has no clue what they’re talking about—but also put their actions in the context of combat: The bomb “did what war does—it destroys people.”

There is remarkably little anger expressed toward America over the bombings, though one woman remembers asking the occupying soldiers why they’d killed her family. (The soldiers, who didn’t understand Japanese, just smiled back.) Much of their bitterness is directed at their own government, which for years neglected to give survivors subsidies, and at their own people, who continue to ostracize them. “The death and destruction was horrible,” one man explains, “but sometimes it’s harder to survive.”

Okazaki uses drawings and painting by A-bomb survivors to illustrate many of the stories, but eventually he shows still photos of Nagasaki the day after it was bombed, with charred bodies lying on what once were bustling streets, and U.S. Army footage of hospital patients (including one of the present-day interviewees) with terrible burns and infections.

These images are horrific, but Okazaki isn’t using them for shock value. Their inclusion is necessary—essential, even—to White Light/Black Rain. There’s no way to discuss this tragedy—or to argue against letting such a tragedy happen again—without showing the results of the tragedy itself, and his steady build toward these horrors only deepens the images’ already considerable impact. That anyone survived such a conflagration is amazing. That anyone would even consider unleashing such a conflagration again is almost unthinkable.

But in a world where the youth don’t know what happened in August of 1945 and where enough nuclear weapons exist to reenact Hiroshima and Nagasaki hundreds of thousands of times over, the almost unthinkable is almost possible.

Ed Moore is a writer and film reviewer living in Chicago.