There were 184 wreaths — one for every life lost when a plane hit the Pentagon 10 years ago — and members of the military stoically and solemnly laid them on benches inside the Pentagon Memorial.

The benches mark each life lost, and they served as the touching, silent focal point for the 1,600 people who watched nearby on a big-screen TV as the wreaths of white flowers were gently laid, one by one, in a patriotic and somber ceremony at the Pentagon marking a decade since the terrorist attacks.

Standing before an enormous U.S. flag draped over the plane’s impact point on the Pentagon, Vice President Biden told the gathering that the terrorists “never imagined that the 3,000 people who lost their lives that day would inspire 3 million to put on the uniform and harden the resolve of 300 million Americans.”

“They never imagined,” he added, “the sleeping giant they were about to awaken.”

To the loved ones of those killed at the Pentagon, Biden said that “those who you lost, who we now call heroes, were already heroes. They were already heroes to you.”

Family members, friends and relatives of the Pentagon victims — there were also more than 100 survivors in attendance — listened intently, occasionally wiping away tears, as Biden, Defense Secretary Leon E. Panetta and the chairman of the Joint Chiefs of Staff, Adm. Mike Mullen, spoke of the dead and the heroes who sprinted to rescue strangers.

At times solemn, at other times stirring and patriotic, the three men spoke with the Pentagon Memorial in the backdrop, in between the Navy Sea Chanters Chorus singing “Amazing Grace” and the Army band belting “The Battle Hymn of the Republic.”

It is difficult to believe,” Panetta said, “that 10 years ago, this was the scene of incredible devastation, of horrific fire and smoke.”

Mullen said, “Dreams were shattered. Futures were instantly altered. Hopes were tragically dashed. You come here — we all come here — to remember those hopes, and to mourn, and to honor.”

The terrorists, Mullen said, “could bring down walls, but they could not bring down America. They could kill our citizens, but they could not kill our citizenship. And in that spirit and with that pride, a whole new generation has been inspired to serve — many of them in uniform.”

Former defense secretary Donald H. Rumsfeld, who helped first responders outside the Pentagon in the moments after the attack, was in attendance, as were House Speaker John A. Boehner (R-Ohio), Sen. Mark R. Warner (D-Va.) and other elected officials and former senior military leaders.

Later in the day, President Obama laid a wreath at the memorial and, with his hands clasped and head bowed, observed a moment of silence. The president and his wife, Michelle, then visited with the crowd at the memorial, posing for numerous photos.

Family members said they were moved by the hour-long service, particularly the way each victim was respectfully and individually honored.