Washington: US President Barack Obama on Monday visited Arlington National Cemetery, as is traditional on Memorial Day, to pay tribute to the country's war dead, whom he said represent "the best" the nation has to offer. Memorial Day, since the end of the Vietnam War, has served to recall the problems confronting veterans upon their return home and those of the families who lose loved ones in combat, EFE news reported. The solemn ceremony at Arlington, where thousands of those who served and died in US wars are interred, began with Obama placing a floral offering at the Tomb of the Unknown Soldier. The president then gave a brief speech in which he emphasised that the troops who rest in the cemetery and their families only ask one thing in exchange for their "heroism" and sacrifices: to be remembered. "The Americans who rest here and their families represent the best of us," Obama said. "They ask of us today only one thing in return - that we remember them." He added that "We have to do better. We have to be there not only when we need them, but when they need us."