Firefighters and civilians from across the nation are dressing in full gear, climbing thousands of steps in honor of those who lost their lives in the September 11 attacks.

Those participating are climbing 110 floors as a symbolic gesture to the brave New York City firemen who selflessly entered the World Trade Center 21 years ago.

In Forsyth County, Georgia, local fire department members and other community members are climbing 110 flights of stairs to honor the victims of September 11 and to raise funds for families of firefighters who have died in the line of duty.

The funds raised for those families will go towards counseling and support programs.

“Even if you’re not a firefighter, to come up here and just to walk the stairs, it’s important to know what those men and women did that day,” John Sexton told CBS 46. “We want to keep their memory alive.”

Elsewhere in the nation, firefighters and other participants in Baltimore walked 110 flights of stairs along the stands of M&T Stadium on Saturday, WJZ reported.

In Jacksonville, Florida, local fireman Nick Bullins is climbing 110 floors on a stair climber at a YMCA on Sunday in memory of the heroic men and women of September 11, CBS 47 reported.

Outside of Colorado Springs, Colorado, firefighters from across the country are climbing the Manitou Incline on Sunday, an event that started in 2015 and has grown larger each year, KKTV reported.

Wearing 60 pounds of gear, firefighters climbed approximately 2,700 steps, with some carrying the American flag during their ascent.

“It’s an honor. It’s a privilege. It’s a way to give back to those who gave the ultimate sacrifice 21 years ago today,” organizer RJ Gerry told KKTV when asked what the climb personally means to him.

Twenty-one years ago, Islamic terrorists took the lives of 2,977 victims in attacks across the nation, including in Lower Manhattan, the Pentagon, and those aboard Flight 93. Among those lost were 343 firefighters in New York City at the World Trade Center buildings.

You can follow Ethan Letkeman on Twitter at @EthanLetkeman.