Hiroshima, Japan, First Atomic Bomb

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  1. Hiroshima, Japan
    1. The Manhattan Project
    2. The political context
    3. Why Hiroshima and Nagasaki?
    4. The Great Little Boy Pump
    5. Three days after Hiroshima, it was Nagasaki's turn.
    6. The participation of Russia
    7. Obama, the first acting U.S. president to visit Hiroshima
    8. From Hiroshima to Hope - Seattle Lantern Festival
    10. The most interesting points for the visit are:
  2. You may be interested:

Hiroshima, Japan

Hiroshima, in Japanese 広島市, is the name of the city sadly known as the place where the first nuclear bomb exploded in history.


On a morning of hot August 1945, when the streets begin their hectic life, a great light invades the sky. A few moments of doubt, uncertainty and an explosion that turns the morning into the night and everything is known ceases to exist.

During the Second World War, the President of the United States, Harry S. Truman, authorized the first bombing of Hiroshima. The justification: Japan had refused to accept the surrender that the Allies had imposed on it through the Potsdam Declaration in late July 1945.

So on August 6, a Boeing B-29 bomber plane, named Enola Gay, dropped the"Little Boy" bomb. The device exploded a 15,000-ton load of TNT, which devastated a range of 13 square kilometers.

At least 70,000 people died that same day. By the end of 1945, however, the death toll had risen to more than 100,000 because of the radiation exposure the survivors had suffered.

The Manhattan Project

In 1939, a group of physicists, including Albert Einstein, wrote a letter to US President Franklin Roosevelt to alert him that in the future, Nazi Germany might have an atomic bomb of terrible destructive force.

The U.S. authorities took the warning seriously and, in the same year, the Uranium Committee was established as part of the U.S. National Defense Commission, which assessed the potential threat and then began preparations for the development of its own nuclear weapons.

By the summer of 1945, the U.S. had three nuclear bombs: two plutonium and one uranium ('Little Boy', the one dropped on Hiroshima). On July 16 of that year, one of them was tested at a test site in New Mexico.

The political context

During the Potsdam conference on 24 July 1945, US President Harry Truman informed Stalin, possibly with a blackmailing intent, that his country had in its possession a weapon of"extraordinary destructive force", but the Soviet leader showed no special reaction.

The British Prime Minister, Winston Churchill, who was present at the conversation, concluded that Stalin did not realize what the new weaponry consisted of.

However, the supreme commander of the USSR was well aware of the Manhattan project and, as soon as he said goodbye to the US president, said to Vyacheslav Mólotov, then Soviet Foreign Minister and first'supervisor' of the Soviet nuclear project:'We will need to talk to Kurchatov physicist in charge of the USSR nuclear project] today to speed up our work'.

Why Hiroshima and Nagasaki?

In May 1945, a meeting at the national laboratory in Los Alamos, California, rejected the idea of attacking military targets with atomic bombs because of the possibility of misdirection and a"sufficiently strong psychological effect".

That's when it was decided to use the new weaponry to attack cities.

The head of the Manhattan project, General Leslie Groves, insisted on dropping the bomb on a Japanese city that had not yet been bombed, in order to better assess its destructive effect.

He proposed the city of Kyoto, the spiritual capital of Japan, but Defense Secretary Henry Stimson dismissed the idea because of his fond memories of this city, where he spent his honeymoon.

Hiroshima's fate was sealed. Sometime after the attack, doctors began to warn that people who appeared to have recovered from their injuries and psychological shock were beginning to suffer from a new disease unknown to date.

The Great Little Boy Pump

Little Boy', exploded when it reached the height of 590 meters, causing an atomic reaction that released an energy of 13 kilotons (equivalent to 13,000 tons of TNT) and generated heat of approximately 1 million degrees Celsius, causing the air to burn and generating a fireball of about 256 meters in diameter.

About 30% of the population of Hiroshima died instantly, being disintegrated by the heat and explosion and creating the so-called'shadow effect'.

Those killed during the explosion or from damage caused by the explosion should be added to those who were affected by the injuries, burns and side effects of the radiation.

Those who survived the catastrophe were known as'hibakusha', which literally means bombed person'.

The ratio of civilians to a military in the city was close to six civilians for every soldier.

The highest post-attack mortality was recorded 3-4 weeks after the explosion. Then, the world learned about the terrible consequences of exposure to radiation for the human body.

Three days after Hiroshima, it was Nagasaki's turn.

On August 9, 1945, a B-29 took off with the nuclear bomb called'Fat Man' with the intention of dropping it on the city of Kokura as its primary target and Nagasaki as its secondary target.

When he arrived in Kokura, the city was 70% cloudy, making it difficult to see. The sky above Nagasaki, however, was clear that day.

In 1950, the total number of victims of the Hiroshima bombing as a result of the explosion and its consequences was estimated at about 200,000 people; in Nagasaki, it was 140,000.

The participation of Russia

Bewildered, he found the Japanese dropping the Hiroshima atomic bomb on Paul Tibbets' B-29"Enola Gay" on August 6, 1945.

According to early reports in Japan, the city had been destroyed by conventional bombardment by many aircraft.

It wasn't until a few days later that no one began to realize the magnitude of the tragedy, thanks to the research of physicist Yoshio Nishina.

Nevertheless, no Japanese politician or military man thought of the word"surrender" in the hope that some miracle would tip the balance in his favour.

Two days after the atomic bombing, on August 8, 1945, the Soviet Union of Iosif Stalin declared war on Japan and the Red Army in an offensive called"Operation Storm of August", invaded the territories under Japanese rule of the puppet state of Manchukuo, Inner Mongolia, Southern Sakhalin, and the Kuril Islands.

In the first 24 hours the Kwantung Army in Manchuria, the most powerful in Japan, was practically annihilated by the Soviets.

Because of these events, for the first time among the Japanese high command, people began to think about the possibility of surrendering, since they had a psychological fear of communism.

However, the United States did not care about Japan's attitude, as it had to wipe Japan off the map as quickly as possible, before the Soviet Union invaded all the territories of Southeast Asia, which would lead to an imbalance of power in the post-war period.

Terrified of this possible outcome, President Harry Truman authorized a second atomic bomb to be dropped on the city of Kokura.

Obama, the first acting U.S. president to visit Hiroshima

On May 27, 2016, U.S. President Barack Obama visited the Hiroshima Peace Memorial.

There he met with Japanese Prime Minister Shinzo Abe to pay heartfelt tribute to the victims. Several survivors of the nuclear attack greeted him during the event, in which he delivered a speech that had never been delivered by an incumbent U.S. president.

Obama said on that occasion:"We come to mourn the dead, including more than 100,000 Japanese men, women, and children; thousands of Koreans; a dozen Americans imprisoned.

Their souls speak to us. They ask us to look inward, to evaluate who we are, and what we can become.

Today, in the area of the bombing epicenter, there is a Peace Memorial Park and a Memorial Museum that pays tribute to the victims and has become a symbol of the tremendous damage that human beings can cause and the need never to go to such extremes again.

From Hiroshima to Hope - Seattle Lantern Festival

This video is dedicated to the hope that we as humanity will grow towards a more conscious and understanding future where we cease to inflict pain and suffering upon our brothers and sisters, and we work to teach our children to do the same.


In today's Hiroshima, what has happened here is only a painful memory and it is shown before us as an industrial and modern city where its inhabitants have turned the page to continue their journey.

To find signs of the event we must go to the area of the Peace Memorial Park, where the main monuments of the city commemorating the tragic event are located. This park occupies the place where before the bomb was the political and economic center of the city.

The most interesting points for the visit are:

Dome or Genbaku dome: it is the main monument of the park as a whole because it remains standing as the explosion left it in 1945 A.D. Originally it was used as the headquarters for the promotion of industry. Surprising it wasn't destroyed when it was so close to zero points.

Children's monument: it is a construction that remembers the children who died due to the atomic bomb.

Next, to the monument, display cabinets hold thousands of paper cranes, sent by children from all over Japan to remember Sadako Sasaki, the Hiroshima girl affected by leukaemia from the explosion.

Admitted to the hospital and following an old Japanese legend that says that anyone who makes a thousand paper cranes will receive a wish. Sadako spent her illness making paper cranes, dying when she had only 644 made.

Peace bell: the large bell that reminds us of the dead. The visitor can ring the bell in his memory.

Flame of peace: on a pond of water lilies is the flame of peace. This will remain until all nuclear weapons are gone.

Cenotaph: it is a monument in memory of the victims of the war. An inscription reads:"Rest in peace. We'll never make the same mistake again."

Memorial Museum: it is a group of two two-story blocks linked by a walkway where there is an exhibition on the nuclear explosion and its consequences on the city and its population. Using original pieces, including some of them interactive, he shows us all the horror he suffered. The ticket costs 200 yen.

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