At 9:02 a.m. on April 19, 1995, a bomb exploded in a truck parked at the north entrance of the Alfred P. Murrah Federal Building in downtown Oklahoma City, killing 168 people and injuring approximately 850 in the worst single act of domestic terrorism in the U.S. at the time. Now, victims, witnesses, and first responders give their accounts of what happened. Watch Oklahoma City Bombing: One Day in America on Sunday April 6th at 9pm on National Geographic UK. | National Geographic UK