A memorial card signed by Housing and Urban Development Secretary Ben Carson, M.D., is attached to the chair of Thomas Eugene "Gene" Hodges Jr. in the Field of Chairs at the Oklahoma City Memorial in Oklahoma City, Wednesday, April 19, 2017. Hodges Jr. worked at HUD and was killed in the Oklahoma City bombing. Survivors and family members of those killed in the Oklahoma City bombing will gather for a remembrance service Wednesday, the 22nd anniversary of the attack. Carson is speaking at the 22nd Anniversary Remembrance Ceremony. (AP Photo/Sue Ogrocki) (Photo Credit: AP)
Brian Martinez, 31, attaches a wreath made of family photos to his father's chair in the Field of Chairs at the Oklahoma City Memorial in Oklahoma City, Wednesday, April 19, 2017, the 22nd anniversary of the Oklahoma City bombing, which killed is father, Rev. Gilbert X. Martinez.Survivors and family members of those killed in the Oklahoma City bombing will gather for a remembrance service Wednesday, the 22nd anniversary of the attack. Carson is speaking at the 22nd Anniversary Remembrance Ceremony. (AP Photo/Sue Ogrocki) (Photo Credit: AP)
Aren Kok, left, talks with Housing and Urban Development Secretary Ben Carson, M.D., right, following a remembrance service of the 22nd anniversary of the Oklahoma City bombing in Oklahoma City, Wednesday, April 19, 2017. Kok is the mother of Baylee Almon, the baby in the iconic Oklahoma City bombing photo of a firefighter carrying a baby out of the rubble. (AP Photo/Sue Ogrocki) (Photo Credit: AP)
Oklahoma Gov. Mary Fallin, center, embraces Vickie Lykins, left, and Angela Richerson in the Field of Chairs at the Oklahoma City memorial following the 22nd Anniversary Remembrance Ceremony, in Oklahoma City, Wednesday, April 19, 2017. Lykins and Richerson lost their mother, Norma Jean Johnson, in the bombing. (AP Photo/Sue Ogrocki) (Photo Credit: AP)
Shirley Ward stands at the chair of her sister, Karen Gist Carr, in the Field of Chairs at the Oklahoma City Memorial following the 22nd Anniversary Remembrance Ceremony in Oklahoma City, Wednesday, April 19, 2017. (AP Photo/Sue Ogrocki) (Photo Credit: AP)
Jamie Hill plays with flowers left at the chair of Baylee Almon, the baby in the iconic Oklahoma City bombing photo of a firefighter carrying a baby out of the rubble, following the 22nd Anniversary Remembrance Ceremony in Oklahoma City, Wednesday, April 19, 2017. Hill would be the second cousin of Almon. (AP Photo/Sue Ogrocki) (Photo Credit: AP)
Oklahoma Gov. Mary Fallin, left, greets Housing and Urban Development Ben Carson, M.D., right, before the start of the 22nd Anniversary Remembrance Ceremony of the Oklahoma City bombing in Oklahoma City, Wednesday, April 19, 2017. Carson is speaking at the ceremony. (AP Photo/Sue Ogrocki) (Photo Credit: AP)
Family and friends of those killed in the Oklahoma City bombing placed wreaths, photos and balloons on the metal chairs that memorialize the 168 people who died in the 1995 attack.
Hundreds gathered on Wednesday at the memorial and museum built at the former site of the Alfred P. Murrah Federal Building for the 22nd anniversary of the deadliest act of domestic terrorism in the country.
U.S. Department of Housing and Urban Development Secretary Ben Carson spoke during a remembrance ceremony. His remarks included the importance of teaching unity to American children.
The Murrah building housed HUD offices as well as employees from other federal agencies. HUD lost 35 employees in the attack.
Timothy McVeigh was convicted of the 1995 bombing and was later executed.