As the Japanese city of Hiroshima marks the 65th anniversary of the world's first atomic bomb attack, a member of the US crew that dropped the weapon talks to the BBC's Kristin Wilson about his memories of that day.
To his family and friends, the elderly man in a little retirement community in Georgia is just "Dutch".
But 65 years ago on Friday, Lt Theodore Van Kirk was flight navigator for the Enola Gay on its mission to drop the atomic bomb on Hiroshima.
On the morning of 6 August, 1945 he, two of the closest friends and nine other Americans took off for the flight that launched the world into the nuclear age.
"I looked out the window and saw the just-rising sun and thought about what a beautiful morning it was over the Pacific," he recalls, sitting in his home office surrounded by pictures, books, model planes, awards and mementos marking the mission.
"We didn't know at first what we were going to do. Just that maybe it would shorten the war."
The bomb killed an estimated 100,000 Japanese, but it ended the war and precluded an invasion of Japan, and Mr Van Kirk says he has no regrets. None of them did.
"Look, we did what we had to do," he says. "They were never going to give up. But I just could not see how they could continue the war and subject their people to that."
He remained friends with bombardier Tom Ferebee and pilot Paul Tibbets until their deaths in 2000 and 2007 respectively. They flew 35 missions together.
'Nine miles away'
In spring 1945, the war in Europe drew to a close while the battle in the Pacific raged on and an allied invasion of Japan seemed imminent.
The crew learned about their mission from the atomic scientists who had come to their base on the island of Tinian. But not even the scientists had all the answers.
"One said, 'We think that you'll be OK if you're nine miles away when the bomb explodes,'" he recalls. "And that kind of got our attention. And we said, 'you think?' They said, 'We just don't know. Probably best to be at least nine miles away.'"
The next order was to go get some sleep.
Mr Van Kirk laughs at the recollection.
Mr Van Kirk, third from left, says he never let the flight define him
"Sleep? After that? There was no way we were going to sleep," he says. "So, we played poker. Tom won. Tom always won at poker."
The morning of the mission arrived. For the flight, Tibbets renamed the plane in honour of his mother. The Enola Gay flew only one mission. As they neared the target the mission remained secret, even for the crew.
"They kept telling us we were going to do something and destroy an entire city," he says, shaking a knowing finger.
"But if you don't know by then what was going on, you were stupid. And if you talked about it, you were even more stupid."
As flight navigator in the days before sat-nav, Mr Van Kirk's job was to guide the plane to Hiroshima by following rivers, towns and landmarks.
The cabin was quiet the whole way there. Unusually for friends so accustomed to jokes and pranks, there was no extraneous talk, no frivolity, only talk that involved the task at hand.
"Then Tom said, 'I have it. I can't make it any better than that. I've got it down the line.'" he recalls.
And the 9,400-lb bomb, named Little Boy, dropped from the plane.
The plane turned hard to the right to escape the blast they weren't sure would even come. But Little Boy detonated 1,800ft above Hiroshima at 8.15am.
"For 43 seconds, nothing happened," he pauses.
"And then there was an orange light so bright from the back of the plane that I think you didn't have on goggles, you'd probably be blind."
About 140,000 people were killed or died within months of the bomb
The concussion rocked the plane like anti-aircraft fire. A second shock wave followed.
"It's like when a rock hits a still pool of water," he says. "That's the best way I can describe it."
After the shock waves subsided, Tibbets turned the plane around to survey. Contrary to reports, Mr Van Kirk flatly denies they circled the target. They just took a look before heading back, because everyone wanted a report, he says.
"General Rose wanted to know, the scientists wanted to know," he says.
"Hell, Truman wanted to know."
Radio operator Dick Nelson, the youngest of the crew at 19, sent word back to command: "Results excellent."
Bob Lewis, the co-pilot, kept a log of the flight, and is remembered for saying the infamous words, "My God, what have we done?"
Mr Van Kirk chuckles.
Yes, Bob did keep a log, he remembers.
Sea of rubble
"But I'm not going to tell you what Bob's first thing was." He pauses. "Let's just say it was - more descriptive."
Even as he sits surrounded by mementos, Mr Van Kirk says neither he nor his friends let that day define their lives.
"We never talked about it," he says.
"We'd talk about playing golf or kids or just go visit each other."
Every year around this time the calls start coming in, he says - requests to speak at high schools, events, public appearances.
"My life now is hectic," he says. "And on the 6th it'll get even crazier. But I won't answer the calls that day. Not that day."
For him, it's a day to remember his friends. Tibbets, whom he visited on his deathbed. Ferebee, whom Mr Van Kirk called every day after he fell sick. A sad smile passes over his face.
Ferebee "told me he was going to die and asked me 'will you say nice things about me?'" he recalls with a chuckle. "I said, 'well, I will if I can think of anything.' We were just friends for life."
A picture in the book stops him.
"This was always the most poignant to me," he says, looking at a photo of a solitary man standing amidst a sea of rubble.
"After the war, we went to Nagasaki before the occupation forces arrived," he says.
"And this Japanese is returning through his home, which no longer exists. Can you imagine? Coming back to your home and finding this?"
His hands spread open over the page. Then he slowly taps the photograph.
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