Thousands of motorcycle riders are in Washington for a parade known as "Rolling Thunder," which comes a day before the Memorial Day holiday honoring U.S. military personnel killed in battle.
The bikers are visiting the Vietnam Veterans memorial Sunday and are then gathering at the Lincoln memorial where there will be speakers.
A musical tribute to Veterans also is to be held today, which will include pop group Paul Revere and The Raiders and singer Nancy Sinatra.
The "Rolling Thunder" event specifically honors missing U.S. soldiers and prisoners of war.
Some information for this report was provided by Reuters.