As the Port Arthur massacre was unfolding Alison Smith made a phone call. The killer answered.

It was a crisp, blue-sky autumn day on April 28, 1996. 

The tourist town of Port Arthur in Tasmania was quite busy, visitors seeing the historic convict settlement and its teeming grounds. On this day, their lives changed irreparably. 

A gunman, 25-year-old Martin Bryant, killed a couple at Seascape Cottage, a bed and breakfast guesthouse property nearby. He then drove roughly five kilometres to the Port Arthur Historic Site and opened fire on staff and guests with an AR15. He shot with savage indiscriminateness, claiming 33 lives inside the cafe, at the gift shop, in the car park and at a nearby toll booth. 

35 people were killed in the massacre.

Also in Tasmania, ABC journalist Alison Smith first heard word of the major incident around lunchtime.

"I was sitting at my desk, writing up the stories for the night's news and an ambulance went by with full sirens. And then a second ambulance went by, full sirens. And a third one straight after that. In Hobart, that was pretty unusual," she told ABC's new show I Was Actually There. The program speaks to people of all walks of life who were present at the scene of major events in Australian history. 

Watch: survivors share their stories. Post continues below.

Upon the breaking news reaching the office, Smith raced to the scene to report on what was happening.

She called Tasmania Police's media unit, and she phoned Seascape Cottage, the guesthouse five kilometres away from Port Arthur, to see if anyone there knew what was going on.

The person who picked up the phone sent a chill down her spine. 

"The phone picked up and all I could hear was this high-pitched hysterical laughter, that just went on for quite a few seconds. Then [he] said: 'I can tell you that I need to take a shower, because right now, I'm covered in blood. And don't think about calling the police. I've got a couple of hostages. If you call the police, I'm going to kill the hostages,'" recounted Smith. "Then the phone dropped out."

It was Martin Byrant. 

By this point, he had finished his attack at Port Arthur and holed himself up in the guesthouse along with a hostage.

Immediately after the call, Smith called the police commissioner's office. Her phone call helped police try to piece together what had just happened, officers racing to Seascape Cottage, assuming the gunman would be located there.

Smith began reporting from the scene, doing pieces to camera, covering the story that became more tragic by the minute. Police crisis negotiators from the Special Operations Group were on the phone to the gunman, trying to assess the situation and just how many hostages he had.

The negotiator asked the gunman how he was, he replied: "Fine, couldn't be better. Just like on a Hawaiian holiday."

When the negotiator pressed him as to what he meant, Bryant replied: "I don't know myself, no."

Reflecting on the conversation, the negotiator told I Was Actually There: "He wasn't reacting the way you would expect from somebody that had just committed the atrocities that he's committed."

When Bryant was taken into custody by armed forces, he was "smiling, semi-naked and burnt" according to tactical officers. 

The Port Arthur Historic Site. Image: Getty.

Bryant ultimately pleaded guilty to all the murders and was sentenced to 35 life sentences plus 1,652 years without parole. He remains behind bars at Risdon Prison Complex, a maximum-security correctional facility near Hobart. He is 57-years-old.

The massacre, which was the deadliest mass shooting by a single person in Australian history, prompted John Howard's Liberal government to introduce legislation heavily restricting the ownership and sale of automatic and semi-automatic weapons, as well as toughening licensing conditions.

The National Firearms Agreement passed in Parliament with bipartisan support just 12 days after the massacre.

In the years following the massacre, many survivors have shared their stories. 

Anita Bingham was then 17 years old and had only been working at Tasmania's Port Arthur Historic Site for about a month. She was a waiter at the Frances Langford Tearooms, one of two cafes at the former convict settlement.

Speaking with Mamamia's True Crime Conversations, Bingham says she undertook several years of therapy to process the events of that day and help manage post-traumatic stress disorder. She is still unsettled by sudden loud noises, like a car backfiring or balloon popping, and struggles to watch movies or TV shows featuring guns. 

For years, she found it difficult to vacuum without checking over her shoulder, or even to go to a cafe.

"I really learned a lot from that day. And what I learned most of all was life is just so short," she said. "I just wanted to live life to the fullest. And I did. That's something that's changed my perspective."

Walter Mikac lost his entire family in the massacre. Previously speaking on Anh Do's Brush With Fame, he spoke about how in the depths of his grief, he managed to make an impact on the world. The passionate anti-violence advocate relentlessly campaigned to have Australia's gun laws tightened.

"I just wish I could give them another cuddle... You think about all the things that you miss out on over their lifetime. Hopefully they're gonna be looking down, if they are, and gonna be saying, 'Dad, thank you. I'm still being remembered [through the foundation]... and I'm helping other children. Our names are being remembered in that way.'"

Feature Image: ABC.