U.S. President Barack Obama commemorated the nation's war dead Monday on Memorial Day, calling on Americans to help the families of the fallen.
"A nation reveals itself not only by the people it produces, but by those it remembers," Obama said at Arlington National Cemetery outside Washington, where he laid a wreath at the Tomb of the Unknown Soldier. "We do so not just by hoisting a flag, but by lifting up our neighbors, not just by pausing in silence but by practicing in our own lives the ideals of opportunity and liberty and equality that they fought for."
In his last Memorial Day ceremony before leaving office next January, Obama noted that less than one percent of Americans are in the military, meaning that many people do not know anyone currently serving in the U.S. armed forces.
He said that more than 20 U.S. military personnel have been killed in Afghanistan and Iraq over the last year, and cited the history of three of their lives leading to their deaths in combat.
WATCH: Obama at Arlington National Cemetery
Obama reflected on the serenity of the gravesites at the cemetery, including Section 60, where U.S. personnel killed in the Middle East in recent years are buried. At Arlington, he said, "the deafening sounds of combat have given way to the silence of these sacred hills.
"For us, the living, those of us who still have a voice, it is our responsibility, our obligation, to fill that silence with our love, and our support and our gratitude, and not just with words, but with our actions," the president said. "For truly remembering and truly honoring these fallen Americans means being there for their parents, and their spouses and their children.
"We are so proud of them," he said. "We are so grateful for their sacrifice. We are so thankful for the families of the fallen."
Earlier, Obama hosted a breakfast for military and veteran service groups, as well as senior military leaders, at the White House.
WATCH: National Memorial Day Concert
Sunday night, a free Memorial Day concert headlined by the 1960s group The Beach Boys was held on the west lawn of the U.S. Capitol.
The event was hosted by actors Gary Sinise and Joe Mantagna, and was broadcast on PBS and the American Forces Network.
The U.S. observes Memorial Day on the last Monday of May.
The first large-scale observance of what was originally called Decoration Day took place at Arlington Cemetery in 1868, three years after the bloody U.S. Civil War that killed more than 600,000 people.
Now, aside from honoring the fallen victims of U.S. wars and military involvement across the globe, the three-day weekend is seen as the unofficial start of the summer vacation season in the United States. Many Americans have the day off from work and school, and many families have picnics or make trips to the beach, parks or campgrounds.