There are few more iconic pictures of the late Diana, Princess of Wales than the one of her walking into and through a minefield in Angola.
She did it in 1997 – just a few months before she was killed in the car crash in Paris.
In an instant, the campaign to ban the use of landmines was front page news – and talked about by political leaders across the world.
But were it not for a director of the British Red Cross at the time, it may never have happened
Mike Whitlam understood very well how Diana’s talents could be used.
Without him, those pictures in Angola would not have happened.
She was very good at lending her fame to causes which others had shunned.
And so, 20 years after the events of 1997, I sat down in a churchyard with Mike Whitlam.
Diana was "very passionate about everything she got involved with," he says thinking back to the trip in January 1997.
It’s easy to forget how Diana was criticised at the time for what she did.
Some ministers in the Tory government at the time thought the Princess had crossed the line into politics.
Diana would later insist she was a "humanitarian figure" and "always would be".
But Mike Whitlam was simply worried he'd placed the world’s most famous women into a minefield.
"I was a bit nervous," he told me, "but I thought the idea of people being able to see that she was prepared to put her life at risk and that the Halo Trust and others were clearing these landmines would mean that people would support the campaign."
Mike was standing just three or four feet away as Diana, dressed in beige chinos and wearing a bomb protection vest and visor, walked through the minefield as the world’s cameras filmed and photographers clicked their lenses.
He recalls Diana's incredible compassion – and talks about that other iconic photo of Diana sitting on a wall with a girl called Sandra who had only one leg.
But Mike also recalls how committed she was to the landmines campaign – asking questions, taking notes and even correcting him at one point when he'd said something inaccurate to a reporter.
As for her son's involvement in landmines tonight, Mike Whitlam says "it’s fantastic news that he’s picking up the baton."
And given Prince Harry’s time in the army in Afghanistan – another country plagued by landmines – Mike thinks Harry "understands, probably more than his mum did, what the issues really are all about."
Prince Harry is now supporting a new push to make the world free of landmines by 2025.
The Halo Trust charity – which also worked with Diana – has calculated it will cost £800 million to clear all the landmines from countries like Angola, Columbia, Afghanistan and Cambodia.
The British government will pledge some money tonight from its (often criticised) overseas aid budget.
It appears that Prince Harry plans to use the twentieth anniversary of his mother’s death to continue and further her work on landmines.
In the words of the man responsible for Diana making it such a big issue two decades ago, Mike Whitlam says, "the fact that there are landmines still hurting people and killing people is outrageous."