What Los Angeles Fire Department Capt. Richard Denning remembers most about arriving at the World Trade Center on the morning of Sept. 12, 2001, were the faces of people handing him photos of their missing husbands, wives, children, and friends.
Everything was gray.
"There was no color. It was just absolutely -- I don't know if a graveyard's a good word. It was just dark, black and white,'' Denning said.
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Ten years after the 9/11 attacks, Denning still has a hard time talking it. It is not what he did at ground zero. It's what he was unable to do that pains him.
Denning led one of 25 Federal Emergency Management Agency, 70-member Urban Search and Rescue, or USAR, teams in the aftermath of the attacks.
His wife woke him the morning of the attacks. He had returned to Los Angeles from a muscular dystrophy softball tournament in Baltimore late the night before. The New York Fire Department team he'd just played lost three firefighters that day.
Denning remembers thinking two things that morning: It wasn't accidental and "How many firemen are going to be going up in that building?''
A total of 343 firefighters died when the towers collapsed.
Denning's USAR team was dispatched almost immediately. He said goodbye to his wife, rushed around trying to say goodbye to his four daughters but missed the two youngest.
Once at March Air Force Base southeast of Riverside, things slowed way down. All flights were still grounded nationwide, and it would take eight more hours before two the transport planes would be allowed to take off, with fighter jet escorts.
Meanwhile, Denning and his team had been briefed that as many as 20,000 people might have been in the two towers.
"I'm thinking about the golden hour, where you save the most lives ... and then the first 24 hours is the golden day, where you have still a good chance. Every hour after that first day it diminishes,'' he said.
It would be about 13 hours after the attacks when Denning's team landed at McGuire Air Force Base in New Jersey.
After a three-hour trip into the city and setting up a camp at the Javits Convention Center, Denning and his crew of firefighters, search dogs, structural engineers and paramedics, were finally in a truck on their way to Ground Zero. But Lower Manhattan was gridlocked, and the 3.5-mile trip took two- and-a-half hours.
"The whole time I'm thinking, `We gotta get there. We gotta get there. We gotta get there,''' Denning said.
People were already cheering for anyone in a uniform, he said, "and you want to slouch down in your seat. You don't want to hear it. It's like, `We've done nothing.'''
He was frustrated -- that one of the nation's best-trained USAR teams could be stuck in traffic.
"We're made for this, but everybody in this gridlock thought they were important, and I don't blame them,'' Denning said. "It's their city. How do you tell them, `Get out of our way. We're from L.A. We're here to save your guys.''
Finally arriving near Ground Zero, Denning found the scene chaotic, intimidating even for someone trained in disaster response.
"You look at the enormity of this and you just think, we are as insignificant as anything in this environment,'' he said.
Hundreds of people were scrambling over a pile of rubble at least seven stories high.
A joint command was trying to coordinate the responses, but it was futile, he said.
"There were no protocols,'' Denning said.
Ultimately his group just spread out.
"Fires were coming out of everywhere. FDNY was doing a great job trying to knock down everything they could, so it wouldn't turn into the next disaster,'' he said.
"You're looking above you and you're seeing the damage in all these surrounding buildings. Pieces of the tower just tomahawked into a 55-story building and took out 30 stories of it.''
Denning remembers the sound of emergency whistles when the wind picked up, creating storms of glass and debris.
Hours into the rescue effort, Denning was uncomfortable.
"You know, these were two office buildings. You don't find a keyboard, a computer screen, a hard drive, nothing, other than major pieces of concrete,'' he said.
The same went for bodies and body parts.
"We were sure we were going to find parts at least,'' he said. "We're used to that. We found nothing.''
Going into the night, a little rain helped knocked down the dust that would later be blamed for a range of 9/11-related maladies.
Finding no survivors was frustrating.
"We weren't finding what we thought we were going to find. We weren't rescuing people,'' he said. "When you go as a rescue team and you don't make rescues, it's hollow ... you were almost ashamed.''
Over his 10 days in New York in 2001, Denning and his crew found solace standing shoulder-to-shoulder with other firefighters and volunteers in long lines of bucket brigades, chatting while moving dirt and debris away from footprint of the twin 110-story towers.
By Day Five, USAR teams began searching the surrounding buildings.
"I remember going into a Marriott Hotel across the street. It looked literally like a movie scene, like a bomb had gone off and this was what was left of this lobby, this beautiful lobby that was just gray and dusty,'' Denning said.
There were eerie scenes of rooms with partly packed suitcases and wallets still on night stands.
"Scenes that you don't ever get used to,'' he said.
Denning and his crew did anything it could to be helpful. Sometimes that meant going to the homes of New York firefighters they had never met and cooking for their families or mowing their lawns.
"We were no longer a true rescue team, we were a humanitarian team,'' he said. "Things turn to recovery sometimes quicker than you'd like. You have to be able to adjust as to what you can do for the local environment.''
The hardest part for Denning, by far, was the support he received from volunteers: food, laundry service, massage offers, thank yous and cheers. He chokes up when he talks about it.
"You never feel right taking something for nothing,'' he said, "but in the end you learn that you have to let people do those kinds of things, because you're helping us recover as a nation. You're helping America heal.''
Denning won't be at the Los Angeles Fire Department's memorial ceremony Sunday. He tries to avoid the thanks and praise, even from his own department.
"I'm working just by chance, Sept. 11. I'm glad I'm here. I want to be back at work,'' he said.