OKLAHOMA CITY (KFOR) – Twenty-one years later, Americans still remember where they were on September 11, 2001.

During the weekend of the anniversary, first responders across the Oklahoma City metro recognized those who lost their lives during the terrorist attack on the Twin Towers in New York City.

A solemn sound rang through Leadership Square and Oklahoma Tower in Oklahoma City Saturday as more than 400 first responders climbed 110 floors, signifying a promise to “never forget.”

On the steps of the Edmond North High School stadium, hundreds more wearing full gear climbed stairs for the same purpose.

“It’s personal for me,” said Patrick Kerby, who was a New York City officer during the attack.  “I was an officer at the time and I was at the Police Plaza two blocks away when the second plane hit the towers.”

Kerby tearfully recounted the moments after the lives of so many Americans changed forever.

“After the towers collapsed, you just put the uniform on, do your job and there was no thinking. I really couldn’t remember. It was just working and do what I had to do.”

Kerby has since moved to Edmond. He was watching as first responders honored those lives lost on 9/11 Saturday during Edmond’s annual Memorial Stair Climb and 5K Run.

“All those men and women in the face of danger that didn’t make it home,” said Kerby. “It makes me feel proud that what they did wasn’t in vain and that they will be remembered.”

Oklahoma Governor Kevin Stitt also stopped by to show his gratitude to the men and women weaving through the stands for the climb.

“Never forget, always remember,” said Kerby.

More 9/11 ceremonies were planned for the weekend across the metro including one Sunday at OSU’s Boone Pickens Stadium.