US president Barack Obama has urged the young people of Northern Ireland to build on the successes of the peace process and strive to heal the divides that still afflict the region.
Addressing an audience of 2,000 invited guests at the city's Waterfront Hall, the majority of whom were school children, the president said it was up to young people to challenge hardened attitudes and prejudices and push the current generation of political leaders to drive towards lasting reconciliation.
"As all of you know all too well, for all the strides you have made, there's still much work to do," he said. "There are still people who have not reaped the rewards of peace, there are those who are not convinced that the effort is worth it. There are still wounds that have not been healed and communities where tension and mistrust hangs in the air. There are walls that still stand, there are still many miles to go."
He added: "Peace is indeed harder than war. Its constant fragility is part of its beauty. A bullet need only happen once but for peace to work we need to be reminded of its existence again and again and again.
"And that's what we need from you. That's what we need from every young person in Northern Ireland, and that's what we need from every young person around the world. You must remind us of the existence of peace - the possibility of peace. You have to remind us of hope again and again and again. Despite resistance, despite setbacks, despite hardship, despite tragedy, you have to remind us of the future again and again and again. I have confidence you will choose that path; you will embrace that task."
Mr Obama, who visited the Republic of Ireland in 2011 but was on his first trip north of the border, pledged America's continued support for Northern Ireland. "For those who choose the path of peace, the United States of America will be with you every step of the way," he vowed. "We will always be a wind at your back. As I said on our visit two years ago I am convinced that this little island inspires the biggest of things. This little island - its best days are yet ahead."
The president said no-one was naive enough to think peace would be anything other than a long journey. "This work is as urgent now as it has ever been because there is more to lose now than there has ever been," he said.
Mr Obama travelled to Belfast with his wife Michelle and daughters Sasha and Malia. A massive policing operation surrounded the visit - part of the wider security efforts aimed a delivering a secure G8 summit at the Lough Erne Golf Resort in Co Fermanagh.
Peter Robinson and Martin McGuinness, the First and Deputy First Ministers of the Stormont power-sharing executive, greeted the president on arrival at the Waterfront and held a brief private meeting before Mr Obama's public address.