This photo taken just moments before a devastating car bomb went off during the Troubles will send a shiver down your spine.

What appears to be a simple photo depicting a smiling father and son on Market Street in County Tyrone is an important piece of Irish history. 

The photo was taken in front of a small red Vauxhall Cavalier car, mere moments before a bomb built into the vehicle detonated, killing 29 people including the image's photographer and a woman who was pregnant with twins.

The incident killed more people than any other during the Troubles (1968-1998)

According to the Occult Museum, Spanish native Gonzalo Cavedo, and his son pictured survived the tragedy. The camera containing the photo was found in the rubble in the aftermath of the attack. 

This week marks the 20th anniversary of the Omagh bombing (which happened on Saturday August 15th, 1998 at 3.10pm)

Devastated families and survivors of the attack, which left 200 people injured, gathered in the Omagh Memorial Garden on Sunday for a service and tribute to the victims.

Read More: Family of little boy killed in Omagh bombing discover recording of his voice 20 years later

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The infamous attack by the Real IRA came just four months after the signing of the Good Friday Agreement.

This job toughens your skin & can harden your heart. Talking to people on the worst day of their lives every day will do that. Not ashamed to say I cried when I hung up with someone who lost their little brother in Omagh bomb, a child the same age as my own son. Heartbreaking

— Leona O'Neill (@LeonaONeill1) August 9, 2018

To date, nobody has been convicted of the crime, which was condemned by former Sinn Féin leaders Gerry Adams and Martin McGuinness.

According to the Irish Post, Irish Minister for Health Simon Harris was in attendance for Sunday's memorial service, while Taoiseach Leo Varadkar was notably absent.

Thank you to the community in Omagh for inviting me to join with you today to mark the 20th anniversary of the Omagh bombing. Honoured to represent the Irish Government & stand with you in solidarity and support. A beautiful commemorative service

— Simon Harris TD (@SimonHarrisTD) August 12, 2018

Minister Harris said that the Irish Government remained determined to bring "those responsible" for the attack to justice.