On the morning of April 19, 1995, a truck bomb exploded at the Alfred P. Murrah Federal Building in Oklahoma City. At the time, it was the deadliest act of domestic terrorism in U.S. history.
The blast was equal to nearly 4000 pounds of TNT. It killed 168 people. Hundreds more were injured.
The federal office building also housed a day care center. The explosives-laden truck was parked directly beneath it.
Of the 21 children there that morning, only six survived.
Christopher Nguyen was one of the survivors. He was 4 years old at the time of the bombing and his mother, Phuong, worked nearby.
Click here to listen to another survivor’s story.
Originally aired April 17, 2015, on NPR’s Morning Edition.