OKLAHOMA CITY - It was an ordinary spring morning on April 19, 1995 - until seconds after 9 am.
That’s when equipment closets of first responders throughout the city would frantically empty.
A bomb had exploded at the Alfred P. Murrah Federal Building.
Seldom seen photos show what firefighters first saw: the smoke so dense it shaded the sun, the first victim found thrown into the street.
“It was just way too much to comprehend everything that was occurring. I was around 24 years old. It was surreal," said Mike Walker, OKCFD Battalion Chief 601. "You knew where you were at. You knew the building you were in. Nothing was recognizable."
And, yet, they entered to save the living and search for those who perished.
Joseph Childers is one of the new generation of firefighters who picks up the equipment and dawns the helmet.
"I was a young child when it happened but, even to this day, I hear incredible stories of guys, the heroic things they did when they were there," Childers said.
Childers is in training for a grueling walk.
He and about 50 other firefighters will enter the 13.2 mile half marathon in full gear.
"First and foremost, you have to get mentally ready," Childers said. "When it's hot like that and you're working, you have to realize it's going to be painful."
The very equipment that protects them during a fire becomes their albatross during the marathon.
The three-layered coat protects them from fire and heat, but Wesley Sitton will tell you “it also prevents our body from cooling naturally. It keeps all that heat built in. Really, the only escape we have is here and here at our wrist."
Their body temperatures can skyrocket during the marathon.
Then, there's the weight.
“It gets heavy with all our tools and our scva air tanks," said Justin Marshall. “We're got about 50-60 extra pounds on us. We're doing a heavy work load with that."
What has become an annual tradition started with only two guys.
"It's grown ever since," said Captain Brad Tobin. "This year, we expected 50-60 firefighters."
It can take firefighters up to four hours to walk the half marathon.
"It's very humbling, actually," said Joe Bennett, Oak Cliff Fire Dept. "It's a great feeling being able to come across that finish lie and finish 13.2 miles."
Cort Smith, the son of a firefighter who worked the bombing, said he adds weight to his training to prepare for the event.
He and other firefighters wait at the finish line for all in the group to cross as one.
The crowd always stands and cheers.
"The crowd cheers for us, but they don't really know what we've done. They're really cheering for the people who came before us," Smith said. "We stand on the shoulders of greatness, so we just try to carry that on."