Four months after the Good Friday Agreement a car bomb ripped through the town of Omagh killing 29 people. It was the worst atrocity in the history of the Troubles.
Click here for the BBC's special report on the bombing.
Two baby girls, five other children, 14 women and five men were among the victims.
The bombing was carried out by dissident republicans calling themselves the "Real IRA", led by a former Provisional IRA quartermaster-general. The Real IRA later apologised for the bombing saying it had intended only to hit commercial targets. It later called a ceasefire to all military operations.
The bombing was widely condemned by both sides. It raised fears that the political groups could not control their military wings. In particular, it increased pressure on Sinn Fein to ensure that weapons were handed over.
But many also sought to find hope in the wreckage, that the atrocity was some kind of last desperate act against the inevitable momentum of the peace process.
However, the Real IRA's apology and ceasefire were shortlived. Dissident republicans went on to carry out a string of sporadic and small-scale bombings in Northern Ireland before turning their attention to London. In a series of publicity-seeking attacks, the group targeted MI6 and the BBC's headquarters.
The pursuit of those responsible has been painfully slow - hampered by a lack of hard evidence.
In 2000, the BBC's Panorama named four men it believed were responsible for the bombing and in 2001 relatives of the victims launched a £1m campaign to raise funds for a civil action against the alleged bombers.