On October 23, 1993, Alan McBride took his wife Sharon to work in her father's fish and chip shop on what he calls a "beautiful morning." It would be the last time he would see her alive. But he can still vividly recall every detail about her.  

"She was a wonderful, wonderful woman, beautiful to look at and to be with," he told DW. "She was funny, she was a grafter — not afraid of getting her hands dirty. She loved her family and adored her daughter, although she only got to spend a short time with her."

The 29-year-old mother was one of 10 people killed when the paramilitary Provisional Irish Republican Army, better known as the IRA which wanted to end British rule, planted a bomb in the shop on the Shankill Road in a largely Protestant Unionist area of Belfast. The target was an office of another paramilitary group, the Ulster Defense Association (UDA), located above the family-run chip shop.

Read more: Past haunts Northern Ireland 20 years after the 'troubles'

"People searching through the rubble for bodies and survivors. The smell of burning debris was very thick in the air. There were sirens and people were screaming — the whole place was just an absolute state of confusion," recalled McBride.

Sharon was one of more than 3,600 victims of the Northern Irish Troubles  — a period of conflict that stretched from 1968 for 30 years. It pitted Nationalists, who want a united Ireland, against Unionists, who want to remain with the UK against each other.

In 1998, the signing of the Good Friday Agreement cemented a hard-won peace. But 20 years on, some fear the UK's departure from the European Union is threatening to reignite sectarian violence in Northern Ireland as old wounds are dredged up.

Read more: Crisis in Northern Ireland as Brexit looms

Everyone suffered during the Troubles

In Newry, a city in Northern Ireland not too far from the border with Ireland, McBride is one of a number of people telling his story to a packed auditorium. Most of the crowd are older and would've lived through the worst of the Troubles.

The event was set up by the Truth and Reconciliation Platform (TARP), an organization formed in the wake of Brexit with the aim of countering radicalization within the Unionist and Nationalist communities and the return to the violence of the past.

TARP's chairman Stephen Travers was a musician with the Miami Showband and lost three of his band mates when they were shot as the group crossed the border from North to South following a concert one night in 1975. He was badly injured in the attack.

For Travers, it's important TARP reaches people from both the mostly Protestant Unionist and the mainly Catholic Nationalist communities as a reminder that "neither side of the conflict, neither community, has a monopoly on suffering or loss." 

"If you have any of these stories and you hold them up in isolation, then they can be used as a stick to beat the other side," Travers told DW. "We're saying that if you do violence, these are the consequences and we think when most people are faced with that, they think twice about it."

The trouble with a hard border

During the Troubles, people had to pass through military checkpoints guarded by British soldiers at the Northern Irish-Irish border. But the 1998 peace agreement ended that, making the nearly century-old, 310-mile long (499-kilometer) border practically invisible and allowing for free movement on the island.

This allowed Irish Nationalists to feel a part of Ireland, while Unionists could pursue continue with their wish of staying in the UK. If the UK leaves the EU without a trade deal, World Trade Organization (WTO) tariffs would kick in, meaning that different customs rules, regulations and standards would need to be enforced at the border.

Reinstating border infrastructure would have a substantial impact on those who lived through the Troubles  — particularly in the Nationalist community, who feel Irish.

"I think the symbolism of it would be significant," said Dominic Bryan, an expert specializing in political anthropology in Northern Ireland at Queen's University in Belfast. "If you had cameras that were just sitting there monitoring border trade and people… The symbolic nature of it sitting on the border is huge and you can guess that some people would see it as a legitimate target."

In that case, fears Travers, police and eventually the military could be brought in to protect the border, "and we have 1969 all over again."

The EU and the Irish and the British governments say they don't want a hard border. But so far, negotiators have not been able to find a solution that satisfies hard-line Brexiteers, Unionists, Brussels and Dublin.

In December 2017, negotiators hit on the "backstop" deal that would come into effect in the event of a no-deal Brexit, and would see Northern Ireland remain in the customs union and large parts of the single market.

But the Northern Irish Democratic Unionist Party, which is propping up British Prime Minister Theresa May's Conservative government, strongly rejects such a backstop on the basis that it would threaten the integrity of the UK and increase chances of a united Ireland  — a red line for most Unionists.

No going back

McBride can't envision a return to the kind of violence that led to the Troubles. But he says the hatred and division that characterized his childhood growing up in a Unionist enclave still exist. The communities still largely vote along the lines of national identity and tensions still flare up occasionally.

"Many of them have no interest in being neighbors and I don't know what can change that. I think if the politicians showed some leadership, that would be a start," he said.

And while McBride says he has not been able to forgive those who killed his wife, he says he no longer feels any anger or hatred. He wants to live in a Northern Ireland where the communities overcome those divisions too.

"One where we can go out, where we can celebrate each other's traditions and each other's culture, and we can have our aspirations to live in the UK or to live in a united Ireland," said McBride. "But where they're just opinions and nobody needs to go out and shoot somebody with a gun because they have a difference of opinion. That's the kind of Ireland I want to live in."