OKLAHOMA CITY - Twenty years ago, a powerful explosion rocked the Alfred P. Murrah Federal Building.
Fifteen children in the day care perished, but six survived.
In the middle of chaos, parents frantically searched for their children from the second floor daycare.
Jim and Claudia Denny had two children in the day care - 3-year-old Brandon and 2-year-old Rebecca.
After the bomb went off, Jim ran towards the Murrah building.
As he got closer to the building, the injuries got worse.
"Four blocks away and a little more blood on their shirts...three blocks away people sitting on the curbings...two blocks, one block away when people had towels on their heads laying down," Jim remembered.
Jim will never forget what he saw that day.
"Looking up at the building and the day care center was blown out of it," Jim said.
Fifteen children inside the day care were killed in the terrorist attack.
"It just came on television. They have a two-year-old red-headed, blue-eyed fair-skinned girl at Southwest Medical Center in surgery," Jim said.
His daughter Rebecca had survived.
"Her whole left side was like a raw piece of meat," Claudia said of her daughter's injuries.
Rebecca was sliced by flying slivers of glass from the front window and had a large wound on her leg.
"She was stuck on a piece of rebar," Claudia said.
A piece of the blue barrels carrying the explosive tore through her cheek.
"On the 8th day, they discovered she had a broken arm," Claudia said. "She didn't look very good, but she was still beautiful to me."
Rebecca's brother Brandon also miraculously survived the explosion.
He suffered a critical brain injury. He was unconscious and unrecognizable, except for one thing.
"Brandon had a paw print birthmark, left leg," Jim said.
Jim and Claudia say doctors weren't sure if Brandon would survive.
"They couldn't tell us for 40 days whether Brandon would live or die," Jim said. "They had to remove a portion of his brain at the time of the surgery. It affected his whole right side and speech."
Although they were seriously injured, many have wondered how the Denny children and four others in the day care survive that day.
"They were at the right place at the right time," Claudia said.
When the bomb exploded, two things happened: the center of the building shot skyward, which pushed the six children farther back as deadly tons of concrete and steel collapsed in front.
Ten days after the bombing, Rebecca got to go home.
Her face tattooed by a terrorist, but she will grow to have no memories of that day.
She is now a 22-year-old senior at Oklahoma State University.
Brandon is now 23 years old and works at Goodwill.
He lost the use of his arm, and his leg is weak as a result of his injuries. He also has speech difficulties.
His friends at work didn't know he was in the bombing, until one day a book was donated and a co-worker picked it up and saw Brandon.
Claudia Denny knows her children were only feet away from having chairs with their names on them.
"My life can be changed in a minute and I found that out April 19, 1995," Claudia said. "Because our world ended at 9:02 and we started a new world at four o'clock when we found Brandon. It can all change in a minute's time."
The Oklahoma City National Memorial & Museum is hosting its remembrance ceremony on Sunday, April 19.
KFOR will provide live coverage of the event beginning at 8 a.m.