"White Light Black Rain: The Destruction of Hiroshima" (HBO/Documentary)

When filmmaker Steven Okazaki took to the streets of Tokyo to ask people what important historical event had occurred on Aug. 6, almost no one knew the answer. This was startling, because what happened on Aug. 6, 1945 -- when the United States dropped the atomic bomb on Hiroshima -- permanently transformed the Japanese nation.

In the 62 years since the only two instances of nuclear warfare in history (the bombing of Nagasaki followed three days later), historians and political activists of all stripes have debated the morality behind the act. Did President Harry Truman's decision to use the bomb shorten the war and save lives, or was it a horrendous war crime that cost the lives of more than 350,000 civilians?

But these arguments, Okazaki believes, have diverted us from looking at the horror of what actually happened, which only increases the risk that it could happen again. His new film,"White Light Black Rain: The Destruction of Hiroshima and Nagasaki" (which premieres Monday on HBO), strives to strip the politics and ideology away from this central event of 20th-century history and explore it through the memories and testimonies of those who witnessed and survived it.

A Japanese-American whose father fought in the U.S. Army during World War II, Okazaki has been, as he puts it, preparing to make this film for 25 years. He has interviewed more than 500 survivors of the Hiroshima and Nagasaki bombings as well as numerous American scientists and soldiers.