On 28th April 1996, more than 500 tourists were visiting the historic site of Port Arthur in Tasmania. At lunchtime, a lone gunman armed with three military rifles and over 400 rounds of ammunition opened fire. By the time the gunman was captured 35 people had died, 23 were injured and countless other lives were changed forever. Galvanised by that shocking event, then Prime Minister John Howard convinced the states to introduce strict uniform gun control. Twenty years on, Australian Story looks back at the legacy of that terrible day - the impact it had on survivors, witnesses, some of whom are talking for the first time, and the nation at large.