More than 30 years after being stripped, bound and paraded through countless Vietnamese villages, Pete Peterson returned to the country as America's ambassador. While there, he shook the hands of his captors - and began a mission to save the lives of young swimmers.

Douglas "Pete" Peterson could have got out of flying bombing missions in Vietnam.

When his number came up - in May 1966 - he had already served in the US Air Force for 10 years, both on home soil and in Germany. Since his wife was pregnant with their third child, he would have been eligible for a deferment - but he didn't apply.

"I was a professional soldier and I did what I had to do and she was a professional military wife and she did what she had to do," he recalls. "But I obviously regret that now."

The job Peterson had to do was fly F-4C Phantom II fighter planes. Taking off in Thailand, almost always at night, and flying right across Laos and into North Vietnam, he bombed enemy transportation routes. He was what was known as a Night Owl fighter pilot.

Image caption A US jet flies over a destroyed bridge in North Vietnam

A rotation lasted 100 missions. Four months into his tour, Peterson had already flown 66 missions - it was starting to look like he might be home in time for Christmas.

Then on 10 September, Capt Peterson and co-pilot Lt Bernard "Bunny" Talley took off to attack a bridge and ferry complex close to Hanoi.

"Unfortunately the weather was worse than forecast and we ended up getting into the clouds. We couldn't see the missile coming," he says.

It almost tore their plane in two. With the rear portion engulfed in flames, Peterson and Talley ejected.

Peterson fell into a mango tree. He was badly hurt, with head injuries, both knees dislocated, a broken leg, arm and shoulder. He ordered Talley to run and evade capture. Peterson took out his .38 pistol and thought seriously about killing himself. In the end he threw it in a ditch. He would try to survive - and the only way he could survive was to be taken in by the enemy.

North Vietnam, 1966

Peterson describes what followed as a catastrophic nightmare.

He was caught by a group of villagers with one rifle between them, which they stuck in his mouth. They stripped him of his clothes, bound him and dragged him back to their tiny village - An Doai - where he was put on display like a hunting trophy. After a while he was moved to another village, where he was interrogated, and then, still in his broken, untreated state, piled into the sidecar of a battered motorbike, and paraded through countless other villages.

Jeering, spitting crowds formed around the motorbike. Peterson still has scars from the rocks that were thrown at him that night.

"I was perfectly fair game for all the locals and they took their shots," he says. "If you stop to think about it, it's quite a natural reaction after having been bombed for several years - they had their chance to get a little retribution."

Image caption Douglas "Pete" Peterson in 2000 and 1973

He was first taken into Hanoi, to the Hoa Lo prison - known to its American inmates as the Hanoi Hilton - and brutally interrogated.

Years later, he spoke of the resolve of US soldiers in Hoa Lo "to take whatever torture was dished out to the point of permanent physical injury or death or something just short of that".

After four days, Peterson was finally transferred to a hospital and from there, to a prison camp south-west of the city, known by US prisoners as "the Zoo". He has clear memories of his prison room.

"It had three air-holes in the ceiling, a trap door in the door which food and so on was passed through, and a bunk, just planks of wood set on concrete pillars - and that was the bed," Peterson recalls. A cane insert prevented him from seeing out of the window.

The Hanoi Hilton Hoa Lo Prison was built by the French to hold Vietnamese prisoners, often political prisoners

During the war it held more than 700 US POWs

US nicknames for the prison's sections included "Heartbreak hotel", "Little Las Vegas" and "New Guy Village"

The "Blue Room" was the place where new inmates were interrogated - many reported being tortured

After the war, the complex was converted into an apartment building, shopping centre and museum

The Hilton Hotel in Hanoi is known as the Hilton Hanoi Opera House Hotel Listen to a programme about the Hanoi Hilton at 12.50 on 28 March, from Witness on the BBC World Service

Those concrete walls were to be Peterson's north, south, east and west for the next three-and-a-half years, with only fleeting breaks every few days to wash or empty his toilet bucket. After that long stint in the Zoo he was transferred to another prison, and then another and another.

"Initially of course the idea is you're going to go home in a couple of weeks," he says.

"After five or six Christmases go by you kind of wonder, well, maybe that plan isn't going to work. And you then take on a mental state that essentially says: 'This is it, this is your life. It's not going to change.'"

Peterson began to "take trips out", engaging for hours on end in a sort of vivid day-dreaming. It was more than a process of recalling his past life with his wife, Carlotta, and his children, or the one before that, on the small plot of land on the outskirts of Omaha, Nebraska, where he grew up with nine brothers and sisters.

It was an imaginative mechanism through which Peterson was able to play out unlived aspirations, going through items on a mental "bucket list" of places he had longed to go to and things he had planned to do.

He didn't know who the president was or that his country had put a man on the moon. He missed seven years of his children's lives. Peterson has referred to the irretrievable basketball games and birthday parties from those years as "time scars".

Back in the US, his wife Carlotta also passed four years without news, since the North Vietnamese did not declare the names of their prisoners. It wasn't until mid-1970 that Hanoi released a propaganda film showing American POWs attending a Christmas church service, in which Peterson's face was clearly distinguishable.

Image caption A glimpse of Pete Peterson in 1970 assured his family he was still alive

At around this time, Peterson was taken back to the Hanoi Hilton. Through a tap code used by the prisoners to communicate, Peterson learned that his co-pilot Bunny Talley had been captured by the North Vietnamese a day or so after him and was also in the jail.

Following the Paris Peace Accords in January 1973, some international representatives came to the Hanoi Hilton and shouted out that they were negotiating the prisoners' release.

The Tap Code US prisoners were often kept in complete isolation but they were able to communicate by a 'Tap Code'. The alphabet was squashed into a five-by-five matrix by combining the letters C and K. To refer to a letter, a soldier would first give a cluster of taps to denote the row, then a cluster to denote the column. Example tap-tap, tap-tap-tap tap-tap, tap-tap-tap-tap = "Hi" "We ultimately passed all kinds of things through the wall," says Peterson. "Even to the extent of poetry and everything else - it was quite effective."

The first inmates were handed over on 12 February. There then followed an agonising wait as the soldiers, increasingly restive and indignant, demanded to be let out. Peterson was in the second tranche to be released, and re-joined his compatriots at 11:50 on 4 March, 1973.

He remained in the Air Force until 1980, retiring as a colonel.

Before the war he had dropped out of college, but he went back to university and collected his bachelor's degree, did some post-graduate work and ended up running a mental health programme at Florida State University.

In 1990, he was elected to Congress on a Democrat ticket, and remained there until 1997. During this period he revisited Vietnam three times in the hunt for information about US soldiers missing in action, the "MIAs" who some believed may still be imprisoned in Vietnam.

These trips were a chance for Peterson to come to terms with his wartime experience, which he had not talked about with his family.

"What I had done was mask it," he later told the San Jose Mercury News, admitting that he still occasionally woke up in a cold sweat.

"It wasn't that the experience was injuring me at all, I just didn't think about it. But when I came here the second time, that was when I said: 'Hey, I am really OK. I have really come to grips with this.' I realised the Vietnamese were coming to grips with it too."

Peterson became a voice for reconciliation. After he chose not to run for a fourth term in Congress, he was approached with a job offer.

"President Clinton contacted me and asked if I would be interested in being a candidate for the ambassador slot in Hanoi, the first one," he says. The first one, that is, since 30 April 1975, when Graham Martin had ascended to the roof of the embassy in Saigon with the stars and stripes tucked under his arm and climbed on to a helicopter.

Just like in 1966, Peterson didn't have to go to Vietnam - and this time he very nearly didn't.

"I was a little concerned. You can go back and visit a country and that's one thing, but going back and being a chief diplomat of a country is quite different," he says.

Image caption Pete Peterson and fellow Vietnam veteran John McCain (right) revisited the Hanoi prison where they were incarcerated - the Hanoi Hilton - in 1993

From one perspective, he was a strange choice. How would the Vietnamese receive a man responsible for 66 bombing raids on the country - raids which Peterson admits probably resulted in civilian casualties? And although he insisted at the time that he would "check hate at the door" would his counterparts in the country buy that, or assume he still bore grudges from his ordeal during the "American War"?

Clinton was insistent and sent some of his aides to Peterson to persuade him. In the end, he agreed.

"I was keen to challenge myself and see if I couldn't go back and right the ship, so to speak, and do something positive after having been involved in a lot of activity that some might conclude was somewhat negative."

I return here not to re-live what was probably the most unhappy day of my life Pete Peterson

He was, he says, welcomed with open arms. The former LA Times journalist David Lamb, in his book Vietnam Now: A Reporter Returns, says that during his four years in Vietnam, Peterson became "a walking billboard for reconciliation".

Lamb says Peterson was so popular that Vietnamese people would often stop him on the street to have their picture taken with him. He got his hair cut for 50 cents from a local barber, ate noodle broth like a local, and on his free days took off into the countryside on a Honda moped.

A special moment came four months after he took up his post in May 1997. On 10 September - the same day he had been shot down 31 years earlier - Peterson revisited An Doai, the village where he had been taken prisoner.

Before the trip, he was apprehensive. "It's a walk back in time," he said. "I don't do that well."

He drank tea with Nguyen Viet Chop and Nguyen Danh Xinh - two of the men who had dragged him back to the village through the rice paddies. And he walked through the fields, holding hands with the grandson of one of his former captors, to the mango tree in which he had fallen 31 years earlier.

Peterson said that day: "I return here not to re-live what was probably the most unhappy day of my life, but to signify to the entire world that reconciliation is not only possible but absolutely the way to reach out."

Image caption Nguyen Viet Chop, one of Peterson's captors, greeted him warmly on his visit

As ambassador, his big political agenda included overseeing a trade agreement between the US and Vietnam. Peterson also made it his aim to see as much of the country as he could. He visited at least one different province each week, always making a point of stopping by a school, a hospital and a company or factory.

It was on his visits to the overcrowded hospitals that he began to adopt his new cause.

"What I realised in these visits was at least half the people being treated in those facilities shouldn't have been there at all because they were suffering from injuries that could have been prevented," he says.

Raising awareness of health and safety became a major goal of his embassy. In his office, a few blocks from the site of the Hanoi Hilton, Peterson began a programme called Safe Vietnam. He applied diplomatic pressure to the Vietnamese government to improve safety practices.

One of the first areas Peterson focused on was the use of helmets for cyclists and moped riders.

He encouraged the Vietnamese to introduce legislation making helmets mandatory and negotiated a deal with the shipping line APL to donate container space to import them. Today, in contrast to most south-east Asian countries, almost all Vietnamese riders wear helmets - they have become something of a fashion accessory. Peterson says that head trauma in Vietnam has been halved as a result.

Image caption Vietnam now has a high rate of compliance with its head protection laws

In 2000, the Vietnamese Red Cross awarded Peterson their Highest Merit award. Already the owner of a US forces Legion of Merit, the ambassador became one of the few US Vietnam veterans - perhaps the only one - to own a medal featuring the face of Ho Chi Minh.

The following year, Peterson oversaw a landmark mortality and injury study, which showed that the leading cause of child deaths in Vietnam was not infectious disease but accidental injury. The results helped focus the work of a new NGO, The Alliance for Safe Children (Tasc), which Peterson set up with his Vietnamese wife Vi Le (Carlotta having died in 1995).

An invisible epidemic? Tasc estimates that in Bangladesh, Cambodia, China, Thailand and Vietnam drowning is responsible for around one in four deaths of children under nine

There is a link to poverty - in poor countries, child-care often falls to siblings or grandparents

80% of children drownings of children under the age of four occur within 20 metres of the home

In some countries, drowned children are never admitted to hospital and are therefore not counted Listen to the Silent Epidemic Browse the documentary podcast archive

"We started to look at drowning prevention specifically, because drowning in our statistics was the biggest killer of children in the countries where we had conducted surveys - it was the biggest killer by far," he says.

Tasc estimates one child drowns every hour in Vietnam. In Bangladesh it's one every 25 minutes. Across Asia, the group estimates the death toll to be between 200,000 and 280,000 children per year - around the same as the total number of deaths from the Asian Tsunami in 2004. Nearly half of these victims are toddlers.

Large parts of south-east Asia are covered in rivers and lakes - around 16% of Vietnam, for example - and although children and their parents bathe at dawn and dusk across the region, relatively few people can swim.

"There is a fear of water," says Peterson. "It is not normal for a family to teach the children to swim, because the parents can't swim, because they are absolutely petrified of water."

Working with the Royal Life Saving Society in Australia, Tasc has developed a drowning prevention programme called Swimsafe. More than 300,000 children in Vietnam and Bangladesh have taken the programme and learned basic survival swimming skills.

Although the programme mainly focuses on rural areas, it is also conducted in the Vietnamese port city of Da Nang, which during the war was the location of a major US airbase. Even though the city has beaches on two sides, the training takes place in inflatable swimming pools to allay parents' fears.

Da Nang's government has now committed to ensuring that, by 2020, every child can swim before leaving secondary school.

Image caption Children in Da Nang learn to swim in a temporary pool

But NGOs always need sponsors to keep programmes going. Tasc suffered a major setback earlier this year when its main funder, the Australian government, said it was no longer going to back the project in Vietnam.

"The real issue is that there is no door in any aid organisation or WHO, Unicef or any of these organisations that says 'Child Injury Prevention'," says Peterson. At times, he is frustrated by what he calls the "follow-the-leader mentality" in the aid sector, which he believes is fixated with countering infectious disease.

Pete Peterson, now 77, is not a man to relax in his retirement, nor is he one to dwell on the past. Years ago, he said that he had no intention of becoming a "career POW" and that God had not saved his life for him to be angry.

"My life was preserved to do something constructive," he told CBS. Years later, he and his colleagues are now desperately trying to scrape together $100,000 to keep Tasc's "foot in the door" in Vietnam.

Almost 50 years after first being sent to the country, Pete Peterson's mission is still incomplete.

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