DALLAS -- There's no doubt it is the most somber of American anniversaries. The 9/11 terror attacks changed New York, the nation, and the world.
One of the many first responders who lost their lives that day was firefighter Stephen Siller.
"We believe he was in the south tower. He was never recovered. He was another great person who died that day," said Frank Siller, Stephen Siller's brother.
Stephen, along with the rest of his fellow firefighters and law enforcement officers, were honored Saturday in Dallas at the 9/11 Memorial Stair Climb.
And it's their sacrifices that won't ever be forgotten, especially by those who were - not only inspired to become first responders because of 9/11 - but still remember it like it was yesterday.
"I was in freshmen year history class. I remember seeing it on the tv," said James Fussner, a firefighter and paramedic for Midlothian. "I always wanted to be one when I was a kid, but I never really pursued it until then. And then as soon as that happened, I remember going to my local fire department and start asking questions."
"I was in 6th-grade English class and the teacher basically said 'something is going on,' turned on the TV, and started evacuating the school," said officer Ryan Claustere of the Addison police department.
"Pretty much the same [as Claustere] except I was in 5th grade," said Adam Hamilton, an officer with the McKinney PD. "And I actually don't remember hearing about it, I don't think until I was on the bus on the way home."
"We were in 4th grade at our Mom's classroom. She was a teacher at the time. And we were watching it on TV and got dismissed from school," said Chris Kincaid, a fireman in Celina. "We understood what was going on, and now it means something a whole lot different."
"I think it was one of the things that drew us into the fire service. Growing up and seeing that every year, on the anniversary, and it kinda touched both of our hearts and led us in that direction," said Chris' brother, Carl.
Certainly, for those of us who were alive on that day 15 years ago, it's something we'll never forget, and can't thank those who paid the ultimate sacrifice on that day - and since then - enough for their service to this country.