Eighty-eight-year-old Shigemi Fukahori greeted the pope with a wreath at ground zero in Nagasaki Peace Park on November 24.
Fukahori was 14 when the bomb fell on Nagasaki. Tens of thousands of people died, including his three sisters and a brother.
"On the day the bomb dropped, I heard a voice asking for help," he says. "When I walked over and held out my hand, the person's skin melted. I still remember how that felt. It shows how awful war can be."
Seventy four years later, Fukahori prays for peace at Urakami Cathedral every morning. About 500 meters from ground zero, it's a place he has been visiting since he was a child. The names of many of the dead, including Fukahori's siblings, are listed on the wall.
"Humans are weak, so we tend to be greedy," he says. "But being selfish doesn't bring peace."
Fukahori was never comfortable sharing his experience and didn't talk about it in public for long time. He thought it would be hard for young people who have never experienced war to imagine what it was like.
"No one can really understand what it was like on that day," he says. "It was not just that single moment -- we are still suffering."
On a visit to Spain about 10 years ago, he met a man who witnessed the carpet bombing of Guernica in 1937. He had been the same age as Fukahori was when the Nagasaki bomb dropped. Fukahori felt that sharing his experience might make a difference in the world.
Since then, he has been sharing his memories of 1945 with young people, both in Japan and abroad. He wants to make sure Nagasaki is the last place ever hit by an atomic bomb.
When the Vatican sent a New Year's card in 2018, it struck a note with Fukahori. It featured a photo of a young boy in Nagasaki after the bombing carrying his dead brother on his back. The pope emphasized the misery of a war, writing " The Fruit of War" on the card.
Fukahori wasn't able to look at the picture at first, but then realized that survivors' voices, including his, were being heard by the pontiff.
"I had been thinking that it is meaningless to share my memories," he says. "But when I saw that the pope was sending that card and looking at reactions, I realized that my stories may have the power to change the world, even just a little"
In Nagasaki, the pontiff prayed for the victims of the 1945 attack saying, "Our attempts to speak out against the arms race will never be enough."
Fukahori felt the message could have an impact. "If everyone takes the pope's message seriously, I believe there will be no more war," he says. "That is what I wish for the most. I know that not everyone will understand the importance of nuclear abolition and that's fine, as long as some people understand. I think it's important that things change step by step."
The pope's visit may be only one step, but people in Nagasaki hope it's one that can move the world closer to peace.