The initial stage of the Omagh Bomb Inquiry begins at Strule Arts Centre.
The first day of the commemorative hearings is remembering two victims from Madrid, Spain.
Twelve-year-old Fernando Blasco Baselga and 23-year-old Rocio Abad Ramos were in NI as part of a language exchange group at the time of the atrocity.
Commemorative hearings are set to last for two weeks, followed by a week of statements by survivors of the atrocity, then a week of stories from emergency service members who dealt with its aftermath.
