NEW YORK (CBSNewYork) – As thousands of people ran for their lives out of the burning towers on Sept. 11, 2001, the brave firefighters from the FDNY ran into harm’s way to save thousands of lives.

The Tower Climb pays homage to the 343 brave firefighters who perished on that day. The event was sold out as 1,000 climbers ran in the footsteps of New York’s Bravest.

“All I could think about is ‘I’m gonna push myself and sacrifice myself in this race for everyone who lost their lives on that day,’” a tearful Tricia O’Hara said.

“When I was running up, all I could think about is the people who were trying to run down to get out of the building.”

The Tower Climb honors the ultimate sacrifice made by Captain Billy Burke and firefighter Stephen Siller on 9/11. Tunnel to Towers is using the funds raised at the event to build smart homes for critically injured veterans.

“It’s the least we could do to help them in this small way and say ‘hey, your sacrifice is not forgotten,’” Stephen Siller’s brother, Frank said.

“When I’m here, I say ‘Steven I miss you so much. I wish you were with me when we were doing this for someone else, but I’m so proud of what you’ve done and you’ve inspired your siblings to do the work that we are doing,” Frank Siller said while visiting his brother’s name at the 9/11 Memorial.

REMEMBERING BILLY BURKE

Captain Billy Burke knew the South Tower had already fallen when he ascended the North Tower. He was in the middle of a rescue effort with a wheelchair bound man and his co-worker when he ordered his crew to get out of the building saying, “I’m right behind you,” while knowing he wasn’t going to get out of the tower before it fell.

“That’s who Billy was as a person. He put his men first and the civilians that they were with first. That was Billy, that’s who he was, that is what he did,” Capt. Burke’s brother, Michael said.

Some of the proceeds go to the Captain Billy Burke Foundation that provides tuition assistance at Burke’s alma mater, SUNY Potsdam, for children of NYC firefighters.

“We are pretty much close to offering a full scholarship now,” Burke added. “I’ve gotta give thanks to Tunnels to Towers. It’s just a privilege and an honor to be a part of their organization and help them build homes, smart homes for disabled vets, contribute to the families of first responders killed in the line of duty.”

SUPPORTING A FLORIDA HERO

The Tower Climb’s honorary starters paid respect to the families of those lost in the shooting at Parkland, Florida’s Marjory Stoneman Douglas high school. Debbi Hixon started the race. She is the widow of Athletic Director Chris Hixon, who was killed saving students.

Chris Hixon’s son, U.S. Marine Tom Hixon, flew in from Hawaii to honor his father and participate in the climb.

“As you are climbing up the stairs you are just thinking about all the people, firefighters that climbed up a similar building on 9/11 to try get people out,” Tom Hixon said.

“That sacrifice, that selflessness, it’s the same thing my father has, same thing he passed onto me.”

“To recognize him in the same sense of first responders of 9/11… It’s so humbling to know that people look at him that way. We do. We loved him. For people that didn’t know him to think the same thing is really humbling,” Debbi Hixon added.

The Tunnel to Towers Foundation gave the Hixon family $50,000 to help with their bills.

“It means a lot. When you lose your partner in your life that you made all these plans with. It helps to know that, that part is not something you have to worry about,” the tearful widow said.

TURNING TRAGEDY TO JOY

This day was full of memories for the past, but for New York State firefighter Jim Busch and his girlfriend Lydia Mazza they created a new memory that will last a lifetime. He proposed, she accepted, and they will never forget the emotional day.

“I thought it was great spot to do it. Especially for the love of my life right here,” Busch said.

Just overwhelmed. Surprised. Enlightened. Totally just ecstatic. Yeah, I know I will be spending the rest of my life with him for sure,” Mazza said.

“I thought it was just a dream, but thanks to the Tunnel to Towers Foundation this came true,” the firefighter added.

The couple married on Aug. 11, shortly after this year’s event.

At the 4th annual Tower Climb, a day filled with so many memories of perseverance, emotions once again ranged from tears of remembrance to tears of joy.