On August 15, 1998, the town center of Omagh in Northern Ireland was destroyed by an explosion. A 500-pound car bomb detonated in the middle of a busy shopping center at 3:10 p.m., killing 29 and injuring over 200. The bomb was planted by the dissident republican group Real Irish Republican Army (RIRA) in protest of the recently signed Good Friday Agreement. In 30 years of civil war, this was by far the deadliest attack.

The conflict (known as the Troubles) between republican and loyalist paramilitary groups started in the late 1960s. Both sides wanted to end the “low-level war” with the Good Friday Agreement of 1998. Plenty of people disliked the terms, but the RIRA was particularly violent. They split from the IRA and continued with bombing campaigns through Northern Ireland.

Until the Omagh bombing, RIRA seemed to actively avoid harming citizens. They targeted commercial sites and typically called authorities ahead of time so that the area could be cleared. The warnings on August 15 were misleading, though; callers hinted that the bomb was near the courthouse. Sadly, this meant law enforcement “evacuated” citizens to the actual site of the bomb. It’s still unclear if this was intentional. Afterward, RIRA members continued to claim that they never targeted civilians.

RIRA didn’t stop the Good Friday Agreement from moving forward. It disarmed the paramilitary groups and established a power-sharing government in Northern Ireland. While it didn’t completely end the Troubles, violence was reduced. RIRA called a cease-fire after Omagh but soon reneged on it. No one was ever officially charged for the bombing, though some have been found liable in civil court.