Hundreds of New York firefighters died when the towers collapsed that day in 2001. Many were trapped trying to save those who couldn't save themselves.
A horrific day we must never forget.
Temple firefighters took steps to make sure of that Wednesday morning.
Firefighters Scott Hoelscher and Cindy Philen were just getting off their shift the morning of September 11.
It was like a bad dream.
"We knew that there were firefighters in that building when it came down," Hoelscher said.
Hundreds of them. Brothers and sisters.
"We don't want to forget any of that," said Philen. "And we don't want to forget anybody that fell before us."
As a way to remember, Temple firefighters climb.
"It was an honor to be able to do this," said firefighter Brett Epperson.
"It hurt me," Deze Van Der Bogart, there to watch, said, "'cause I used to be a volunteer fireman" in his home state of New York.
Up and up they went, all 13 floors of Temple's Kyle Building. All together, one set of stairs for every firefighter who died.
That morning, 343 firefighters ran up flight after flight of the Twin Towers, never to walk back down.
The names of all of the fallen were read as the responders climbed.
"I was afraid I might cry because I had two fathers and two sons on my list," said Pam Dragoo, one of the people who read a section of the list of names.
A list that just kept going. A list we'll never forget.
"Two hours and our country's never been the same," said one firefighter.
"It's just a small way of saying thank you," said Hoelscher.
A very small way, for those who gave as big as they could.