The signs of division are still all too evident in the Ardoyne area of north Belfast, an Irish nationalist stronghold bordering pro-British communities where Brexit is creating growing unease.
The murals celebrate guerrilla fighters from both sides, walls mark borders between Catholic and Protestant communities and riots sometimes break out during annual marches by unionist supporters.
But relative peace has prevailed for more than 20 years in an area where hundreds of lives were lost in a period of strife known as "The Troubles" that largely ended with a peace agreement in 1998.
Charity workers say that is partly thanks to the European Union, which has poured hundreds of millions of euros into areas like the Ardoyne, funding projects aimed at reconciling the two communities.
Those funds are now in question as Britain prepares to leave the European Union, and some are warning that the peace process itself could be under threat.
"Our peace process has definitely been supported by the European peace funds -- it has been propped up in some respect by the European peace funds," said Alan McBride, head of the Wave Trauma Centre, a non-profit organisation that supports the victims of violence.
The centre in north Belfast receives a "sizeable chunk" of its funding from the EU, and McBride said uncertainty about what will happen after Brexit makes long-term planning all but impossible.
"We've been told that our funding is probably going to be okay -- at least the money coming from Europe is going to be okay -- up until 2020 but beyond that, we're just not so sure," he said.
Wave provides counselling and psychotherapy, including for those who continue to endure intimidation from paramilitaries.
"This isn't only about the Troubles, this is about last week," he said.
Paramilitaries still mete out punishment beatings on those who break unwritten codes in parts of Belfast.
In January, a police officer was wounded in a gun attack in the Ardoyne blamed on republican dissidents.
Andrew McCracken, chief executive of the Community Foundation for Northern Ireland which disburses grants to various charities, said many organisations were facing similar problems.
"There is uncertainty about Brexit and what that would do to funding that comes from the EU," he said.
The Republic of Ireland has also voiced concern and said it will press the EU to continue "the range of EU policy supports to Northern Ireland and the peace process, including in relation to EU funding".
Brussels has helped bankroll peace efforts to the tune of 1.3 billion euros ($1.4 billion) since 1995 with a further 1 billion euros for cross-border initiatives that are due to run until 2020.
In Northern Ireland, social alienation has often found a home in paramilitary organisations. The vast majority of members were recruited in disaffected working-class areas like the Ardoyne.
During The Troubles, north Belfast suffered more than most areas, accounting for 563 deaths of the near 3,500 total across the British-ruled province.
Despite two decades of relative calm, unemployment in parts of Belfast is still much higher than the national average and the appearance is one of urban decay rather than regeneration.
Brexit has also exacerbated divisions between Northern Ireland's two main parties, with the left-leaning Irish nationalists Sinn Fein supporting EU membership and the main Democratic Unionist Party opposed.
While a 52-percent majority in Britain as a whole opted to leave the bloc, Northern Ireland voted by 56 percent to stay.
John McCorry, formerly the head of the North Belfast Partnership, said funding was needed now more than ever because of growing polarisation between the two communities.
McCorry's charity was recently forced to shut down after 20 years when it failed to secure money from the latest EU funding tranche.
"For the last two years we have been unable to pull down EU funds and this has contributed hugely to our decision to wind up," he said.
McCorry said Brexit was the final straw for his organisation because it "kills any prospect of a return of funding after 2020".