(CNN) Editor's Note: The atomic bomb attacks on the Japanese cities of Hiroshima and Nagasaki had, by the end of 1945, taken well over 200,000 lives. Many of those not instantly vaporized by the fireballs were left with horrific injuries. More would die from the effects of radiation or endure lifelong health complications. When CNN's Will Ripley moved to Japan in 2014, he expected to encounter anger over America's wartime actions. Then he met 79-year-old Hiroshima survivor Shigeaki Mori.
Shigeaki Mori was eight years old on August 6, 1945. He was walking to school at 8:15 a.m. when an American B-29 bomber, the Enola Gay, dropped the A-bomb nicknamed "Little Boy" on Hiroshima.
"I remember the blast suddenly hit me from above. I was blown off the bridge and fell into the river. Because the river was shallow...and the waterweeds growing thick, I survived without injuries and burns," Mori says.
Every weekend for more than 20 years, Shigeaki Mori made long distance calls to the U.S. to locate families of American POWs that died at Hiroshima. He only had a list of names but eventually found the families by calling every matching name in phone books he borrowed from the library.
Crew members of "The Lonesome Lady," an American B-24 bomber. Five airmen crashed and became POWs in Hiroshima, later dying in the atomic bomb attack.
American POW, Norman Roland Brissette, was the youngest airman killed in by the Hiroshima A-bomb when he was 19-years-old. Shigeaki Mori tracked his family in the U.S. and gave details of his captivity, and registered his name on the official list of survivors.
Mori pictured at primary school, top row left. This is his only childhood photo that survived the A-bomb blast.
Japanese public broadcaster NHK collected the drawings of A-bomb survivors. This one shows U.S. prisoners of war (POWs) being taken by Japanese Military Police.
Mori's old primary school was 400 meters from ground zero. He says all the teachers and students in the building died. A police headquarters holding a small group of American POWs sat next to the school. Mori says he saw the captured airmen from his schoolyard. Some Hiroshima survivors even drew sketches of them.
What Hiroshima taught the world
Lost American lives
Today, we know 12 American POWs died as a result of the A-bomb in Hiroshima. The POWs included the crews of two downed American bombers -- the Lonesome Lady and the Taloa.
The youngest, Airman 3rd Class Norman Roland Brissette of Lowell, Massachusetts, was just 19. But due to extreme secrecy and political sensitivity, it wasn't until the 1970s that de-classified U.S. documents verified the presence of American POWs there. And even then, surviving families knew very little of the circumstances surrounding their relatives' captivity and deaths.
The first use of the atomic bomb
The United States detonates the world's first atomic bomb at a test site in New Mexico on July 16, 1945. Less than a month later, atomic bombs were dropped on the Japanese cities of Hiroshima and Nagasaki. The devastation led to Japan's unconditional surrender and brought an end to World War II.
In 1939, physicists Albert Einstein, left, and Leo Szilard drafted a letter to U.S. President Franklin D. Roosevelt, urging him to research atomic bombs before the Germans could build one first. By 1942, the United States had approved the top-secret Manhattan Project to build a nuclear reactor and assemble an atomic bomb.
In 1942, U.S. Army Col. Leslie R. Groves, left, was appointed to head the Manhattan Project. On the right is physicist J. Robert Oppenheimer, who led the Los Alamos National Laboratory in New Mexico.
Los Alamos workers pose on a platform stacked with 100 tons of TNT. It was to be used to gauge radioactive fallout.
The Manhattan Project also involved research facilities in Oak Ridge, Tennessee, and Hanford, Washington. Billboards, like this one in Oak Ridge, reminded workers of the project's top-secret nature.
Workers in New Mexico attach a bomb to a tower two days before its successful test in July 1945.
Trinity was the code name of the test bomb, which was detonated in the Jornada del Muerto desert.
Air Force Col. Paul Tibbetts waves from the pilot's seat of the Enola Gay moments before takeoff on August 6, 1945. A short time later, the plane's crew dropped the first atomic bomb in combat, instantly killing 80,000 people in Hiroshima.
An aerial photograph of Hiroshima shortly after the atomic bomb, nicknamed "Little Boy," was dropped.
U.S. President Harry Truman, aboard a U.S. Navy cruiser, reads reports of the Hiroshima bombing. Eight days earlier, Truman had warned Japan that the country would be destroyed if it did not surrender unconditionally.
A white silhouette on a Hiroshima bridge shows an area that wasn't scorched by the bomb. It was reportedly the outline of a person's shadow -- someone who was shielded from the blast's heat rays by another person.
An elderly victim is covered with flies in a makeshift hospital in Hiroshima.
A worker stands next to an atomic bomb, nicknamed "Fat Man," hours before it was dropped on Nagasaki, Japan, on August 9, 1945.
This photo was taken about six miles from the scene of the Nagasaki explosion. According to the Nagasaki Atomic Bomb Museum, photographer Hiromichi Matsuda took this photograph 15 minutes after the attack.
Survivors of the Nagasaki bomb walk through the destruction as fire rages in the background.
A woman and a child walk in Nagasaki on the day of the bombing. More than 70,000 people there were killed instantly.
Members of the White House Press Corps rush to telephones after Truman announced Japan's surrender on August 15, 1945.
An aerial view of Hiroshima three weeks after the atomic bomb.
Soldiers and sailors on the USS Missouri watch as Japan's formal surrender is signed in Tokyo Bay on September 2, 1945.
Mori, a local historian, felt even Japan's former enemies deserved closure. He was determined to uncover details of the POWs situation, share the information with their families, and ensure that the American names were placed on the wall of the Hall of Remembrance in Hiroshima Peace Memorial Park, alongside the tens of thousands of other victims.
We can still achieve a world without nuclear weapons
Decades of searching
Long before internet searches and easy access to information, Mori had only a list of twelve POW names a local professor gave him. He borrowed American phone books from the library.
For more than 20 years, he spent weekends going down the list of names and making calls from his home in the hills overlooking downtown Hiroshima. For some with common surnames, it would take several years to find their families.
"My phone bills were huge. My wife was upset about it," Mori says.
Mori speaks only a few words of English, so he relied on operators to ask the relatives if anyone in their families died in the A-bomb.
Drawings show haunting memories of Hiroshima
The
Hiroshima Peace Memorial Museum has collected thousands of drawings made by survivors of the atomic bombing of Hiroshima, Japan. The drawings document survivors' memories surrounding that horrible day. In this rendering, Hideo Kimura shows burned and screaming classmates. Some were trapped under heavy gates and houses. Others were in the river, holding onto a stone embankment.
This drawing by survivor Akira Onogi shows a woman pinned under a pillar from her collapsed house as deadly flames approach. Next to the woman, a sobbing girl pleads for help from neighbors. The neighbors couldn't move the pillar.
Chisako Sasaki drew this image of a girl at a window on the second floor of a burning house. Sasaki remembers the girl crying for help. "I can never forget," Sasaki said.
Mitsuko Taguchi is haunted by this scene, depicted in her drawing, of a dead mother and child who had fallen while trying to outrun flames. "Her hair was standing on end," Taguchi said. "She still protected her child under her breast, like a living person. Her eyes were open wide. I cannot forget that shocking sight."
Torazuchi Matsunaga remembered soldiers carrying children's corpses on stretchers to a temporary crematorium. "These children had been injured by the bomb and taken to the army hospital for treatment but had soon died," she said. "The hands and legs sticking out of the stretcher swung with the motion. My chest suddenly seized with emotion."
Survivor Asako Fujise drew this image of a bomb shelter that was being used as a makeshift hospital. It was "filled with moans and the smell of zinc oxide and Mercurochome mixed with sweat."
Sueko Sumimoto remembered a mother standing on a bridge. She was screaming her child's name while the bodies of dead students floated on the river below.
Hiroharu Kono drew a picture of her search for missing family members. Three days after the bombing, she arrived at where her house once stood. "Fires were still burning here and there, and the streets were so hot I could hardly get through," she said. After digging through a foot of dirt, Kono found the bones of her older brother, older sister and a 3-day-old baby who had all died in a fire. "I put my hands together and just prayed to Namu Amida Buddha," she said. "I wept and wept."
Not all the drawings depict bad memories. Masaru Shimizu remembers being given a few dozen frozen mandarin oranges by the military. "I gave some of them to relatives who were seriously injured by the atomic bomb," she said.
Soldiers had been trained not to give water to burn victims, thinking it would worsen their condition. Keiji Harada remembers girls asking her for water. "While I was rushing to get them water, a military policeman yelled at me to stop. When I remember, I deeply regret that I obeyed. I should have found a way to help them."
The memory of seeing two girls with blue-violet faces shocked Torao Izuhara so much that she never forgot it. Their faces were "swollen so badly that you couldn't tell whether their eyes were open or shut, and their skirts were ripped up right at the creases," Isuhara said. "Their faces were really even blacker than the drawing. They helped each other walk along, their shoulders joined together, their powerless legs somehow carrying them off towards the Otagawa River."
Like cattle, injured survivors were loaded into rail cars to escape the ruined city. "Most people were injured, and those with burns were slathered with white medicine," Kazuo Koya said. "There were so many bandaged people. With only the clothes on their backs, they waited under the blazing sun for departure."
Sumie Sasaki was fortunate enough to find a bit of beauty amid all the horror. "The stars were beautiful," she recalled. "My father gathered charred tin sheeting and broken planks and built us a shack over the burnt ruins of his company. One plant's tall smokestack remained standing, and it scared us at night. But the stars glittering all around the scary smokestack were so beautiful."
"At the beginning, they didn't understand why I was doing this and they wondered how I reached them. They were very skeptical and it took a while to gain their trust," Mori says.
The American families were skeptical that Mori wasn't asking for money to undertake the tedious process of helping them complete the Japanese language paperwork to have the American POW names and photos added to the Hiroshima memorial. It took decades of phone calls and letters to complete the process. Mori gave the POW's families previously unreleased details of their captivity, and offered to register their names on the official list of victims.
Opinion: When Hiroshima speaks, President must listen
70th anniversary of the bombing
Despite decades-long friendships forged with those American families, Mori says he never expected what is scheduled to happen on Friday, when President Obama is set to become to the first U.S. president to visit the site of the first atomic bomb attack.
Officials said Obama won't apologize for Truman's decision, but he will offer reflections on the devastating toll of war on innocent civilians.
"Never in my lifetime did I think an American president would visit Hiroshima. I think it is wonderful that he will visit Hiroshima to mourn for all victims of war," Mori says.
As I sit next to Mori in his modest living room, walls lined with historical books much like my father's own library, I tell him it is remarkable what he has accomplished. Not only was he able to locate these families without relying on Google, but he also overcame the hatred he must have felt towards the U.S. -- the country that dropped an A-bomb on his city -- killing members of his family, his friends and neighbors.
"Thank you very much," he says tearfully in English. "Don't mention it."