On September 11, 2001, then Australian Prime Minister John Howard was in Washington when hijacked planes crashed into the Pentagon, the twin towers of New York's World Trade Center, and a field in Pennsylvania.
"Well, it was quite extraordinary. The sense of shock, and outrage and disbelief was palpable. The other thing I remember though is that the country reacted with remarkable calm," he told SBS.
"This was a more devastating attack on the American homeland than Pearl Harbor. It claimed more lives and, of course, it struck at the heart of both the financial representation of America, as well as its military.
"And it was completely unprovoked. People have to remember that America had not done anything to deserve this, and that added to the sense of outrage and disbelief that people had."
Mr Howard's immediate concern that day was for his wife, Janette, and son, Tim, who were also in Washington and had left the hotel to do some sightseeing.
The former Prime Minister told SBS his closeness to the tragedy played a role in strengthening his reaction in the aftermath.
"Yes, it had an impact. It always does if you are there and you have a greater understanding of the implications of such an audacious attack.
"And the respect that I had for the way in which Americans responded in a calm but deliberate way was no doubt about their sense of outrage, and there was no doubt they had every right to feel this was a completely unjustified, unprovoked attack on many innocent people. So it did, it left an indelible impression on me, as you might expect."
He again defended criticisms of his decision to follow then US President George Bush and British Prime Minister Tony Blair into war, denying any links drawn between their interventions and the current crisis in the middle east.
"Well certainly, the current conflict with Islamic State is not the result of our intervention in Afghanistan and Iraq. That's an absurd proposition," he said.
