On April 19, 1995, a domestic terrorist truck bombed the Alfred P. Murrah Federal Building in downtown Oklahoma City, OK. The blast killed 168 people, including 19 young children who were in the building's day-care center at the time.
On April 19, 2000 the fifth anniversary of the attack, the Outdoor Symbolic Memorial was dedicated. Part of the Memorial includes 168 empty chairs representing those who lost their lives. They sit on the site where the Murrah Building once stood.