More than 300 witnesses are expected to give evidence as part of a massive inquiry into child abuse in Northern Ireland.
Public hearings into claims of sexual, emotional and physical abuse in Northern Ireland will be held in Banbridge, Co Down, for the next 18 months.
Chairman of the inquiry Anthony Hart said victims would at last have the satisfaction of knowing that their stories were being listened to.
"This may be a challenging process for everyone involved but it is our hope that everybody, whether from government or from the institutions, who is requested to assist the inquiry will co-operate in a fair, open and whole-hearted way so that this unique opportunity will not be wasted."
The independent Historical Institutional Abuse (HIA) Inquiry is hearing abuse claims from children's homes and juvenile justice centres over a period spanning more than seven decades and has the power to compel witnesses and refer evidence to the police for criminal investigation.
Its aim is to establish if there were "systemic failings by institutions or the state in their duties towards those children in their care".
It was created in response to a campaign for justice by victims, which became increasingly urgent in 2009 following the findings of a similar investigation in the republic, which uncovered evidence of endemic abuse.
The three-member expert panel will examine allegations of physical, sexual and emotional abuse dating from 1922 to 1995.
A total of 434 people have contacted the inquiry to claim they were abused.
About a third of the applications are from people who are now living outside Northern Ireland, including the republic, Australia, Britain and other countries.
Evidence is due from more than 300 witnesses, including former residents who claim they were abused as children, those who ran institutions, health and social care officials and government representatives.