Thursday marks 17 years since the Alfred P. Murrah Federal Building in Oklahoma City was destroyed by a bomb.
On April 19, 1995, the blast killed 168 people including 19 children all under the age of 6. Hundreds more were injured.
At 9:02 a.m., 168 seconds of silence was observed at the Oklahoma City National Memorial on the site where the federal building once stood. Following the moment of silence, the April 19 Remembrance Ceremony began at the Outdoor Symbolic Memorial and including a reading of the names of those killed in the attack.
The ceremony was expected to last about an hour.
The memorial will be open Thursday, free of charge.
Timothy McVeigh, Terry Nichols and Michael Fortier were all convicted in the plot. McVeigh was executed in 2001 while Nichols is serving a life sentence without the possibility of parole. Fortier struck a plea deal, served 12 years and is in the witness protection program after testifying against Nichols and McVeigh.