A new survey asked Australians to rank the 'most significant historic events of their lifetime'.
The passage of same-sex marriage has topped September 11 and the arrival of the internet as the most historic event to impact Australians, according to a new survey.
The survey, conducted by the Australian National University's Social Research Centre, asked 2074 people aged between 18 and 93 years old to choose the top 10 most significant events for the nation.
Same-sex marriage legislation was ranked in first place as it was named by 30 per cent of survey participants.
It was followed by the September 11 attacks, Kevin Rudd's apology to the Stolen Generation, the Port Arthur Massacre and the 2000 Sydney Olympics.
The survey was conducted in late 2017 - around the time of the same-sex marriage postal survey and subsequent announcement of the results.
But there were noticeable differences across generations.
For Generation Z and millennials, the same-sex marriage passage was the most frequently mentioned event.
For Generation X, it was September 11.
For baby boomers, it was the Vietnam War and for those born before 1945, it was World War II.
The Social Research Centre also asked participants what made them most disappointed in Australia, with "treatment of off-shore asylum seekers" topping the list.
Historian and project contributor Frank Bongiorno told SBS news the timing of the survey would likely have boosted the ranking of same-sex marriage – but this did not take away from its significance.
"It gives us an insight at that moment into the way people were placing the event in historical terms," he said.
"(This was) often presented by some politicians, particularly those opposed to it, as a kind of second-order issue ... Well, this survey suggests that a large number of people see it as historically very significant."
Mr Bongiorno said there were several omissions that surprised him.
"Surprisingly, very few people identified Australia's post-war immigration program," he said.
"And there was absolutely no sign of ... the fall of the Berlin Wall and end of the Cold War."
He also said economic events such as the Global Financial Crisis and the floating of the dollar were not given the prominence he expected.
The full list
1. Same-sex marriage - 30 per cent
2. September 11 - 27 per cent
3. The Apology - 13 per cent
4. Port Arthur Massacre - 13 per cent
5. Sydney 2000 Olympics - 12 per cent
6. The Dismissal - 12 per cent
7. Vietnam War - 11 per cent
8. Moon landing - 9 per cent
9. The internet / WWW - 9 per cent
10. America’s Cup win - 8 per cent, Global Financial Crisis - 8 per cent, First female PM - 8 per cent
*Source: Top 10 Most Significant Historic Events in Living Memory, The Life in Australia Historic Events Survey