Those of us who are old enough can remember where we were or what we were doing when news came through of President Kennedy's assassination. Younger folk will have a similar feeling about the events of September 11, 2001.
Now we have the Queensland flood disaster of January 2011 which must surely leave an indelible impression in the minds of those either close enough to have been affected or who watched the drama unfold on their television news.
For me there is a collection of sights and sounds that I will never forget. These are just a few:
A helicopter pilot who saved countless lives while his own family were being evacuated from their flooded home, breaking down on television because he didn't save more.
News of a man's body found 86 kilometres from where he had been swept away by what has been described as an inland tsunami.
The same inland tsunami being described as being more than a kilometre wide.
Three distressed horses treading water, their heads resting on a roof.
The Vietnam veteran who, with just a tin dinghy and a rope towed them, and 7 others, to safety where a vetinerary surgeon donated 5 hours of his time to tend to their injuries.
The 13-year-old boy, Jordan, who begged rescuers to save his mother and younger brother first and who was swept away, along with his mother, by the time they returned to save him.
News of the sighting of a bullshark in the main street of Goodna, a suburb of Ipswich, an inland city.
News of a Rockhampton man sighting about 15 snakes a day.
Following the call by the Brisbane Lord Mayor for volunteers, the sight of 12,000 of them armed with mops, buckets and brooms scrubbing houses and streets.
The sight of the Lord Mayor himself, covered in mud, filth and sweat in 30 degree heat, scubbing the street along with dozens of other volunteers, not even looking up to the camera for a photo opportunity.
The sight and sound, day in, day out during the State-wise crisis, of Queensland Premier Anna Bligh being honest and forthright, with no sign of the usual gaggle of spin doctors, providing up to date information and statesmanlike leadership we have not seen in a politician for a long time.
Being informed by a friend of his daughter who attends university in Brisbane, coming home to find drain pipes had backed up spewing mud all over her house. But before her tears had dried 30 strangers materialised from nowhere and cleaned it up for her.
And on it goes.
It makes one proud to be an Australian, particularly one from Queensland.