Setsuko Thurlow was 13 years old and standing only a mile away from ground zero when the United States dropped an atomic bomb on the Japanese city of Hiroshima in 1945.
More than 72 years after that horrific day, she will jointly accept the Nobel Peace Prize on behalf of this year's laureate, the International Campaign to Abolish Nuclear Weapons (ICAN), an organization in which she has played a major role.
"I remember a bluish-white flash. My body was flung into the air, and I remember a sensation of floating," she said in an interview with AFP, describing the day of the bombing.
Thurlow suddenly found herself pinned under a collapsed building with dozens of others people. A stranger eventually pulled her out.
"The city I saw was almost indescribable," she said.
It was 8:15 am in Hiroshima and the sun had been up for nearly two hours, yet darkness covered the ruins.
"It was like the morning had turned to night," Thurlow said. "The dirt and particles from the mushroom cloud had prevented the sun's rays from getting through."
It was eerily quiet: "Nobody was yelling, nobody was running. Survivors didn't have the physical or psychological strength. All they could muster was a faint whisper, begging for water."
Thurlow said she looked around and saw thousands of people who were "badly burned and swollen. They no longer looked human. That image burned into my retina."
"As a 13-year-old high school student, I witnessed my city destroyed. It had become a city of death."
An estimated 140,000 people were killed in the atomic blast on August 6, 1945. Another 80,000 would die in the bombing of Nagasaki three days later.
Sharing 'painful memories'
Now 85 and living in Canada, Thurlow tells her story widely—to school children and diplomats alike—in order to bring attention to the horrors of nuclear war in the hope of stemming nuclear proliferation.
She has been a leading figure in ICAN since its launch in 2007 and played a pivotal role in the UN negotiations that led to a treaty outlawing nuclear weapons in July, the group said in a statement.
"I keep recalling these painful memories so that people who have never experienced such devastation can understand," she said.
"It's very difficult for many people to understand, but it's extremely important that we use our ability to imagine (these horrors), and together we can stop this from ever happening again."
Reflecting on the current state of affairs, Thurlow lamented the proliferation of nuclear weapons to nearly 15,000 since the World War II, although arsenals are down significantly from a peak in the mid-1980s.
"The world is a much more dangerous place now," she said.
Thurlow condemned US President Donald Trump and North Korean leader Kim Jong-Un's threats of war and personal insults that have sparked global alarm.
And she rebuked Canadian Prime Minister Justin Trudeau for not signing the Treaty on the Prohibition of Nuclear Weapons in July.
A spokesman for Canada's foreign ministry said, "progress on nuclear disarmament and non-proliferation must involve states with nuclear weapons," which Ottowa does not have.
The situation on the Korean peninsula, Thurlow said, "is very frightening, even for a person like me who experienced the first atomic bombing."
"I'm very worried."
The octogenarian urged citizens of the world to get involved in nuclear anti-proliferation efforts.
"We all have to do our part," she said. "Don't just leave it to the fading memories of Hiroshima and Nagasaki survivors."
"No other human being should ever experience the violence of nuclear weapons. Never again."
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