The crisp peal of a memorial bell penetrated the morning air as Arlington emergency workers, city officials and other mourners gathered Wednesday to mark the anniversary of the Sept. 11, 2001, terrorist attacks.

Arlington Mayor Robert Cluck, Fire Chief Don Crowson and Police Chief Will Johnson presided over a solemn 9/11 ceremony at Heroes Park, a memorial that honors the City of Arlington's Police and Fire departments and commemorates those fallen in the line of duty.

Two hook and ladder trucks held a suspended American flag to mark entry to the area, and officers' badges bore black tape symbolizing lost comrades. Uniformed personnel and honor guard members saluted as another American flag was lowered to half-staff amid the bugle strains of "Taps."

The ceremony was among countless others held across the country to mark of the 12^th anniversary of the attacks on the World Trade Center and the Pentagon that killed nearly 3,000 people.

"Today we remember because it is our honor, our duty," Crowson said. "Not just 343 firefighters, 60 police officers, numerous EMS responders and other volunteers who rushed to save those in harm's way, ultimately giving their lives." ??

Cluck quoted a proclamation from President Barack Obama recognizing the annual Patriot Day and National Day of Service and Remembrance that was established to honor those lost on Sept. 11.

"Twelve years ago this month, nearly three thousand innocent men, women, and children lost their lives in attacks meant to terrorize our nation," Cluck read. "They had been going about their day, harming no one, when sudden violence struck. We will never undo the pain and injustice borne that terrible morning, nor will we ever forget those we lost.

"Today, we can honor those we lost by building a nation worthy of their memories."

Crowson reminded those gathered that police and firefighters put their lives on the line every day to protect others.

"The men and women of today's fire service are confronted with a more dangerous work environment than ever before," he said. "We, of course, continually change our strategies and tactics to accomplish our task. Our methods may change, but our goals remain the same: to protect those we serve. This is what we do. This is the tradition of firefighters and certainly police officers."

As part of that tradition, and as a reminder of those who have been lost, the honor guard rang a gleaming bell with a special signal: three rings, three times each, representing a firefighter's "last alarm."

Crowson said the quiet ceremony reminded everyone of those who made "the supreme sacrifice."

"For us, it's a matter of honor and loyalty to our public safety partners," he said. "We're a family, and family never forgets."

Cluck said it's important for the public to recognize the important work of emergency responders.

"We tend to take them for granted," he said. "But every day when they go to sleep, they don't know what will happen."