Arlington , Virginia ( CNN ) -- President Barack Obama led the nation 's Memorial Day observances Monday , laying a wreath at Arlington National Cemetery 's Tomb of the Unknowns and declaring that Americans owe `` a debt to our fallen heroes that we can never fully repay . '' `` The blessings we enjoy as Americans came at a dear cost , '' Obama told a crowd at the cemetery 's Memorial Amphitheater . `` To those of you who mourn the loss of a loved one today , my heart goes out to you . ... This day is about you . And the fallen heroes that you loved . '' Obama names new head of Joint Chiefs . Military servicemen and women killed while serving their country `` gave of themselves until they had nothing more to give , '' he said . `` It is their courage , their unselfishness , their devotion to duty that has sustained this country through all its trials and will sustain us through all the trials to come . '' We need to hold `` their memories close to our hearts and ( heed ) the example they set , '' he said . Obama visited Arlington 's Section 60 -- a burial site primarily for soldiers killed in Iraq and Afghanistan . U.S. and coalition casualties in Iraq and Afghanistan . Earlier in the day , the president and first lady Michelle Obama hosted a breakfast for Gold Star families at the White House . Gold Star families are those who have lost relatives serving in the military . The president was joined for the ceremony at Arlington by Defense Secretary Robert Gates and Joint Chiefs of Staff Chairman Adm. Mike Mullen . Both men are retiring later this year . `` It is up to us to be worthy of ( the ) sacrifice '' of the fallen , Gates said . `` For the rest of my life , I will keep these brave patriots and their loved ones in my heart . '' `` God bless our fallen , the missing , and their families , '' Mullen said . `` And God bless America . ''
President Arlington lays a wreath at the White House . Obama tells Americans to honor the values of fallen servicemen and women . Obama is joined by Joint Chiefs of Staff Secretary Gates and Joint Chiefs of Staff Chairman Gates . The Obamas host Gold Star families at Arlington National Cemetery 's Tomb of the Unknowns .