Steve McCurry never realised, when he heard young voices in a refugee tent at Nasir Bagh, near Peshawar, Pakistan, in 1984, that the picture he was about to take would be on the cover of National Geographic and be named the magazine's "most-recognised photo" ever.
He stepped into the tent and saw almost instantly that Sharbat Gula, the 12-year-old Afghan girl with piercing green eyes sitting in the corner, was the image key to his refugee story. She had never been photographed.
McCurry clicked his shutter, immortalising her forever, and catapulting himself to greater fame.
It is this kind of serendipity that led McCurry to become one of the world's most famous documentary photographers. He began taking photographs as a journalist in 1974, and in 1979 was working his way around Asia, selling photographs to small magazines to keep himself travelling.
It was a year after the Soviet-backed coup in Afghanistan. A grouping of warlords, nationalists and Islamic fighters known as the mujahideen were on the Pakistani border, fighting back. McCurry was in the small town of Chitral, watching thousands of refugees arriving from Afghanistan. Some of them asked him to go and document what had turned into a civil war.
The insurgents dressed him in old Afghan clothes and he trekked with them for several days, over a pass in the Hindu Kush. This was his first war zone. All he had was a Swiss army knife, a cup, two cameras, four lenses, a bag of film and some packets of airline peanuts.
A month later the US began to offer secret arms and funding to the mujahideen. The conflict would later escalate into a full-scale proxy war between the US and the Soviets, but McCurry didn't know that. He only knew he was crossing a border without a passport, going into a forbidden area, and then a war.
It was tough and dangerous, but he stuck it out for three weeks, surviving on sign language and Afghan hospitality. He photographed people's daily lives, using black and white film, often considered to embody the "essence" of a photographic image.
McCurry smuggled the rolls of film back across the border, sewn into his clothing, and three months later his first image appeared in the New York Times, just as the Soviet involvement was becoming a massive international story.
The editors at the Associated Press and the New York Times knew they had found a brilliant new documentary photographer.
THE LURE OF AFGHANISTAN
McCurry returned to Afghanistan in 1980 for Time magazine. The war was considerably "hotter" with US military backing. It helped, of course, that he had dark hair and a thick beard and blended in with the Afghan people.
He later covered the Iran-Iraq war, the civil wars in Lebanon and Cambodia, the Islamic insurgency in the Philippines and the Gulf War. McCurry was driven to show the devastating toll war takes on humans, animals and the landscape.
He almost drowned in India and survived a plane crash in Slovenia. Renowned for his ability to photograph difficult subjects, he often had to shoot in extreme conditions such as monsoon rain (India), snow (Afghanistan), dust storms (India), oil mist (Kuwait) and extreme cold (-50ºC in Pakistan).
He has braved dangerous situations such as land mines in Kuwait, hijacking and hostage-taking in Yemen, ice crevasses in Pakistan, and the collapse of the World Trade Center twin towers in the 9/11 attacks. He has also faced more than his fair share of the bureaucratic obstruction that appears to confront anyone who lifts a camera to their eye.
The trauma of what he has sometimes had to witness is made easier by the distance created by the viewfinder, the knowledge that he is documenting "the story", so that the world will know. Keeping a dispassionate eye while maintaining an emotional connection with your subject is a tough line to tread, but McCurry mastered it.
In Kuwait, embedded with US forces during Operation Desert Storm, he traversed the "Highway of Death", saw the desert sands turned from yellow to black and witnessed what he calls a "scene of the end of the world" - an apocalypse of 600 oil wells set on fire by the retreating Iraqi forces.
His lyrical, sombre photographic style is deliberate. "I like a rich, dark look," he says.
His talents include intuition, perseverance and the patience he learnt from his long-held fascination with Buddhism ("the picture will come to you").
When that Afghan girl cover of the June 1985 National Geographic struck a chord with millions of people around the globe, McCurry did not even know her name. Nearly two decades later he returned with a National Geographic TV crew to try to find her.
It was not easy. Sharbat, who was 12 and a Pashtun orphan when he took her portrait, is in her 40s today, with four children. McCurry says: "Her skin is weathered; there are wrinkles now, but she is as striking as she was all those years ago."
He says each individual picture's own light, tone and structure are key to his work. "I tell stories, but I strive for individual pictures that will burn into people's memories."..