Survivors and family members of those who

died in the bombing of the Oklahoma City federal building will

gather at its former site Monday to commemorate the 15th

anniversary of the deadliest domestic terrorist attack in U.S.

history.

Hundreds of people are expected at the Oklahoma City National

Memorial to remember the 168 people who were killed in the April

19, 1995, explosion at the Alfred P. Murrah Federal Building. More

than 600 others were injured in the attack that caused hundreds of

millions of dollars of damage in parts of downtown Oklahoma City.

U.S. Department of Homeland Security Secretary Janet Napolitano

is scheduled to speak during a ceremony that is scheduled to begin

shortly before 9:02 a.m., the moment when the terrorist bomb was

detonated in 1995.