In Bali they don't mark anniversaries of tragic events. Or rather they did not, before two terrorist attacks tore through the island on October 12, 2002, and, then again, three years later. Out came people from Australia and other nations - survivors, relatives, witnesses, the public at large, declaring their need to mark, commemorate and erect monuments. And so overwhelming was their need that Balinese people moved to make room for our yearly dances of commemoration. Strange it may seem, but public commemorations of tragic events are not universal or compulsory. For the people of Bali, once the purifications ceremonies are complete, anniversaries can serve to re-awaken the evil spirit, to inflict spiritual harm on the community and the dead. Yet for countries outside Bali, whose nationals died in the blasts, Australia, England, America, 21 altogether, anniversaries commemorating the terrorist attacks have effectively functioned as the sacred rites, the ultimate tributes to the victims and their legacy. Today, on the 10th anniversary of the Port Arthur mass shooting, it is vital that we recognise that public anniversaries are not an inherent or undisputed part of civic life.