Among those being remembered are two people from the midlands.
An online ceremony is taking place today for the 800 people in Ireland who remain missing.
It's the eighth annual National Missing Persons Day.
Among those being remembered are Tullamore's Fiona Pender, who was last seen in August 1996, and 33 -year-old Peter Wilson from Rochfortbridge, who went missing while on holidays in Tenerife in March 2019.
The all-island event is a chance for families to talk about their loved ones and appeal for any information which may try to resolve the cases.
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