In a powerful tribute marking the anniversary of the September 11, 2001, terrorist attacks, Orlando Airport firefighters (ARFF) donned full safety gear and participated in a commemorative 9/11 Memorial Stair Climb on Friday.

As radio transmissions from September 11th played in the background, firefighters climbed the equivalent of 110 stories—the height of the Twin Towers—by walking up and down staircases in Terminal B. The climb served as a reminder of the sacrifices made by fallen first responders.

The Transportation Security Administration also joined in the remembrance by holding bell-ringing ceremonies at the security gates.

At 8:46 a.m., the airport observed a moment of silence in memory of the victims.

This year marks the 25th anniversary of the 9/11 terrorist attacks.

We will never forget those we lost, the heroes, those who carry on, and the sacrifices made by so many.