(CNN) -- Bagpipers set the mood on a gray morning in Washington on Friday as President John F. Kennedy's last living sibling participated in a wreath-laying ceremony commemorating the anniversary of his death to an assassin's bullet in Dallas 50 years ago.

The ceremony, featuring Jean Kennedy Smith, was preceded by a solemn visit to Arlington National Cemetery by Attorney General Eric Holder, setting off a nationwide day of commemorations of Kennedy's death.

As it did five decades ago, the nation's attention will settle on Dealey Plaza in Dallas, where a moment of silence is planned at the moment Kennedy was shot....