This year marks the 20th anniversary of the largest act of domestic-borne terrorism in the United States. On the morning of April 19, 1995, a bomb exploded at t...
Moment of Silence People bow their heads during 168 seconds of silence at the Oklahoma City Memorial in Oklahoma City on Saturday, April 19, 2014 during a ceremony to mark the 19th anniversary of the Oklahoma City bombing. (AP Photo/Sue Ogrocki)