People in Northern Ireland need to leave their bunkers and build new relationships across the sectarian divide, the Irish President has said.
If they limit themselves to friendships with those who share their views they will lead "narrowing and diminished" lives, Mary McAleese told a Londonderry audience during one of her last official visits to Northern Ireland.
Mrs McAleese said residents in the city were neighbours.
"That community, like the family if it is to flourish, if it is to be fair, has to let itself be comfortable with diversity and inclusivity," she said.
"The openness that faces with genuine curiosity the very otherness of others is far from easy to embrace but we have all paid too high a price for insisting on living inside bunkers where only those who agree with us are welcome and where the voices of the excluded other are muted or silent."
Mrs McAleese is approaching the end of a presidency which was marked by the state visit to Ireland by the Queen last May which was seen as a gesture of reconciliation between the two islands.
The president added: "To open ourselves to stories, narratives, perspectives, talents, genius, insights and friendships which are new to us is to open the doors of our lives to a much more exciting and enriching landscape."
Mrs McAleese was the inaugural speaker at the first Conversations Across Walls and Borders event in First Derry Presbyterian Church.
The president said the dignified and impressive response to last year's publication of the Saville Report into Bloody Sunday showcased how far people had travelled beyond the days of antipathy and enmity.
"The people of Derry on all sides have given inspiring example and have courageously led the way from mutually enslaving recrimination to mutually empowering reconciliation," she added.