The world changed for John Howard at 9.45 on the morning of September 11, 2001.
The prime minister who had met President George W. Bush the day before was preparing for a routine press conference when American Airlines Flight 77 was crashed into the Pentagon just across the Potomac.
"It was one of the most searing experiences of my time as prime minister," he says 20 years later.
The fuel caused a devastating inferno, and 125 military personnel and civilians were killed along with all 64 people on board the Boeing.
"We were all shocked," Mr Howard says. "There's no other way of describing it. Nobody expected it.
"And when you have such an unexpected shock like that, it does take a while to assimilate it. And you get on with the next thing."
He called the deputy prime minister John Anderson. "John and I just talked very briefly," Mr Howard said.
Earlier that morning, he had talked on the phone to the treasurer, Peter Costello, about the collapse of Ansett.
"People were asking, as they always do, for money, and he was quite rightly pointing out that we weren't in the business of bailing out corporations. He didn't need to persuade me of that, but we talked about it."
And then, in a moment, history changed. Mr Howard found himself bundled into a bunker beneath the Australian embassy where there was "an atmosphere of shock and bewilderment".
He didn't talk to President Bush - he obviously had other things on his mind. America had been attacked.
The footage of George W Bush that day shows him also in "shock and bewilderment", continuing to read a story to school-children as he took stock of the momentous events.
"I just sent him a message," Mr Howard said.
The next day, Mr Howard had been due to address both houses of Congress. "Obviously, that wasn't going ahead. But I thought it would be appropriate if I could attend the special joint sitting.
"I got a very gracious standing ovation, which was very touching and moving and, in the circumstances, entirely appropriate because we would again be a very staunch ally of the United States."
He talked to the two senators from New York, Hillary Clinton being one.
"And then I went with my wife and son, I went to a memorial service at the National Cathedral in Washington."
A day later, a US military plane flew them to Hawaii where he caught a Qantas flight home.
His government decided quickly that Australia would be part of the 51-country alliance that attacked the Al Qaeda hide-outs in Afghanistan.
"I have absolutely no regrets about the decision my government took 20 years ago to involve this country," Mr Howard says. "It was the right thing to do."
But he would not be drawn on whether it was wise to stay for so long and to leave in such disarray.