Oklahoma City Bombing Update

It was one of the darkest days in American history. On April 19, 1995, a powerful bomb ripped through the Alfred P. Murrah Federal Building in downtown Oklahoma City, claiming the lives of 168 people and injuring hundreds more.

Soon after, police arrested Timothy McVeigh and his accomplice, Terry Nichols. Both men were anti-government extremists with military backgrounds.

In June 1997, McVeigh was convicted of 11 counts of murder and conspiracy. Four years later, he was executed at a federal prison in Terre Haute, Indiana. Nichols is currently serving life in prison.

Since that tragic day, the bombing site has been transformed into a moving memorial, which is made up of 168 empty chairs for the 168 lives lost. Two of those chairs belong to Colton and Chase, brothers who were among the 19 children killed in the building's daycare.

Their mother, Edye, was working a few blocks away when the bomb exploded and her life changed forever. For years, Edye says she suffered from intense grief. "I felt empty inside, and I couldn't imagine myself ever being happy again," she says. "I was hopeful, but I couldn't see it."

Today, Edye has two children, 11-year-old Glenn and M.J., who just turned 3. After getting rid of the negative in her life, Edye says she reached a turning point. "Within the past four years or so I've been able to really discover who I am and to just be happy," she says.

There's one Oklahoma City bombing survivor Oprah will never forget. She first met P.J. in 1995, just two days after the explosion. He was 19 months old and one of only six children who made it out alive.

P.J. had burns over half of his tiny body, and his lungs were irreversibly damaged. Doctors weren't sure if he'd survive.

Fourteen years later, P.J. is alive and thriving. He's now free of the tracheotomy tube he wore for years to help him breathe. "Without the trach, I can go to school with everybody else," he says. "I was so excited, the first thing I did was I learned how to swim. … I'm more hopeful now, and I try harder because I know that God has a plan for me."

P.J. still receives two breathing treatments every day, but he has big dreams for the future. Someday, he says he'd like to go to college and become a mechanical engineer. "I believe he's going to make it," Oprah says.