According to a survey , published in late January 2018 by the Social Research Center along with the Australian National University , same-sex marriage was ranked the most historic event to have shaped the lives of Australians . 30 % of the survey participants named the legalisation of same-sex marriage as the most historic event in their lifetime , 27 % named the September 11 attacks , 13 % named former Prime Minister Kevin Rudd 's apology to indigenous Australians and another 13 % named the Port Arthur massacre
September 11 attacks
September 11 attacks
Same-sex marriage in Australia