Why the US dropped an atomic bomb on Hiroshima

On this date 74 years ago, the US dropped the first of two atomic bombs on the Japanese city of Hiroshima, killing more than 70,000 people instantly.

A second bomb followed three days later over Nagasaki and killed 40,000 more.

The US remains the only country to ever use an atomic bomb in war.

The nuclear warfare ushered in the end of World War II and a devastating chapter in world history. Here’s what you need to know about the attacks and how Hiroshima honors those who died.

Where is Hiroshima?

The city is the capital of Hiroshima Prefecture located in southwestern Japan on the island of Honshu.

Peace Memorial Park

The Hiroshima Peace Memorial Park is located atop the busy commercial district obliterated by the atomic blast and contains monuments dedicated to the thousands killed in the explosions.

The recently renovated Peace Memorial Museum sits across the Motoyasu River from the iconic “A-Bomb Dome,” the skeletal ruins of the former Hiroshima Prefectural Industrial Promotion Hall.

The dome was designated a UNESCO World Heritage Site in 1996. The organization described the structure as “a stark and powerful symbol of the most destructive force ever created by humankind; it also expresses the hope for world peace and the ultimate elimination of all nuclear weapons.”

Room for reflection: The Hiroshima Peace Memorial Museum reopened on April 25, 2019, following an extensive two-year renovation. Click through gallery for more photos:

Personal impact: The restored space includes personal artifacts and clothing that belonged to bomb victims.

Visitors gather: The museum, which originally opened in 1955, attracts more than 1 million visitors a year.

Emotional experience: It's estimated that the Hiroshima bomb killed around 135,000 people. Visiting the space is an emotional experience.

Genbaku Dome: Visitors to the city can also see Hiroshima's Atomic Bomb Genbaku Dome -- a UNESCO World Heritage Site. When the United States dropped the bomb on August 6, 1945, it exploded just above the building.

See the renovated Peace Memorial Museum in Hiroshima

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In May 2016, Barack Obama became the first sitting US president to visit Hiroshima. He called for a “world without nuclear weapons.”

“A flash of light and a wall of fire destroyed a city and demonstrated that mankind possessed the means to destroy itself,” he said during an address at the site of the first bombing.

Population

1.17 million, according to a 2010 Japanese census.

Population in 1945

Between 300,000-420,000, according the Department of Energy and the City of Hiroshima website.

The bombing

Then-President Harry S. Truman authorized the attack on Hiroshima. The US B-29 bomber aircraft, the Enola Gay, dropped the nuclear bomb, codenamed “Little Boy,” on August 6, 1945.

Why did the US do it?

American scientists working on the Manhattan Project had successfully tested a working atomic bomb in July of 1945 after the surrender of Nazi Germany in May.

Truman had tasked a committee of advisers, chaired by Secretary of War Henry Stimson, to deliberate whether to use the atomic bomb on Japan.

Sam Rushay, the Supervisory Archivist at the Harry S. Truman Presidential Library in Independence, Missouri, told CNN: “At the time, there was a wide consensus in support of the decision to strike among the members of the committee. Stimson was very adamant that the bomb be used.”

Charles Maier, a professor of history at Harvard University, said that while it was possible for Truman to have made another decision, he said “It would have been hard to justify to the American public why he prolonged the war when this weapon was available.”

“It seemed to offer a potentially magical solution that would spare a lot of pain,” he told CNN.

Maier, who teaches a course on World War II, said Japan was not ready to surrender unconditionally and there was a concern that a weapons demonstration would have not done the job. Such a demonstration would have detonated a nuclear weapon in a non-inhabited but observable area to compel Japan to surrender, an approach that was favored by a group of scientists and Assistant Secretary of War John McCloy, according to Rushay.

He added that Truman and his military advisers feared a “very costly invasion” of Japan.

“The recent experience in the battles in Iwo Jima and Okinawa was very costly in terms of US and Japanese casualties, despite the destruction of the Japanese air force and navy,” Rushay said. “There was a widespread belief among American military planners that the Japanese would fight to the last man.”

Maier said, “Suicide attacks are fairly common today, [but] at the time, the Japanese use of suicidal Kamikaze attacks had made a strong psychological impact on US military decision-makers who reckoned that the whole country would be mobilized to defend the home islands.”

“The US military was unwilling to say it could win the war without the bomb,” he added.

Maier said some historians have speculated that the possibility of the Soviet Union’s entry into the war helped spur the decision to bring the war to a quick end by using the bomb.

Rushay said that Hiroshima was one of four potential targets and that Truman left it up to the military to decide which city to strike. Hiroshima was chosen as a target because of its military importance. Nagasaki was bombed a few days later.

The US remains the only country to have used nuclear weapons.

What was the result?

At least 70,000 people were killed in the initial blast, while approximately 70,000 more died from radiation exposure. “The five-year death total may have reached or even exceeded 200,000, as cancer and other long-term effects took hold,” according to the Department of Energy’s history of the Manhattan Project.

The US dropped another bomb on Nagasaki, Japan, on August 9, 1945, killing up to 80,000 people. Japan unconditionally agreed to accept the terms of surrender on August 14.

What do the critics say?

The utter devastation caused by the bombing has led many to criticize the decision.

In his 1963 memoir, “Mandate for Change,” former President Dwight D. Eisenhower criticized the use of the atomic bombs, saying they weren’t necessary to force the surrender of Japan.

Maier said that the Hiroshima and Nagasaki bombings “did move the Japanese Emperor to intervene with a divided military and advocate for surrender.” But he added that Japan may have been willing to end the war with conditions like keeping the emperor in place.

In 1958, the City Council of Hiroshima passed a resolution condemning Truman for refusing to express remorse for using atomic bombs and for continuing to advocate their use in an emergency situation. The resolution said the city’s residents “consider it their sublime duty to be a cornerstone of world peace and no nation of the world should ever be permitted to repeat the error of using of nuclear weapons.”

The resolution called the ex-president’s stance a “gross defilement committed on the people of Hiroshima and their fallen victims.”

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."

Drawings show haunting memories of Hiroshima

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Defense of the bombing

Truman responded to the Hiroshima resolution by writing a letter to the Council’s chairman, saying that “the feeling of the people of your city is easily understood, and I am not in any way offended by the resolution.”

However, Truman stressed the necessity of the decision referencing how the US had “been shot in the back” in the Pearl Harbor attack by Japan and saying that the decision to use the two nuclear bombs saved the lives of 250,000 Allied troops and 250,000 Japanese by helping to prevent an invasion.

“As the executive who ordered the dropping of the bomb, I think the sacrifice of Hiroshima and Nagasaki was urgent and necessary for the prospective welfare of both Japan and the Allies,” Truman concluded.

How do the Americans and Japanese feel about it?

A 2015 Pew Research Center survey found that only 14% of Japanese thought the bombing was justified, while 79% said it wasn’t. A Gallup poll conducted immediately after the bombing in 1945 found that 85% of Americans approved of Truman’s decision. But the Pew survey last year found that the share of Americans who believe the use of nuclear weapons against Japan was justified had fallen to 56%.