Washington - Tens of thousands of motorcyclists rumbled through the heart of Washington on Sunday in an annual "Rolling Thunder" tribute to US military veterans and war dead.
The cyclists came from across the country, many carrying or wearing the stars-and-stripes of the American flag, as they rolled noisily around the National Mall, the federal capital's grand central esplanade, under the eyes of thousands of spectators.
The Rolling Thunder movement was founded in 1988 by a Vietnam War veteran named Ray Manzo who wanted to draw the attention of both the administration and the broader public to American soldiers missing in Vietnam since that war ended in 1975.
The first edition of the parade drew some 3,000 to 5,000 bikers, many of them active military personnel or veterans. But the numbers soared in following years.
Organizers estimate that as many as 900,000 people -- cyclists and spectators -- now take part each year.
While attention to Vietnam-era troops still missing in action (MIAs) has waned over the years -- some 1,600 have never been accounted for -- veterans of the conflicts in Iraq and Afghanistan, as well as Vietnam, say they often feel isolated and forgotten once they return to civilian life.
And many face the deep frustrations of dealing with a health-care and social-support system for veterans that has often been criticised as inefficient and sometimes inadequate.
But Rolling Thunder, they say, gives them a sense of solidarity and a contact with the public that boosts their morale.
"It's very heartwarming to see people supporting military and former military," said Bob Vaillancourt, 50, a veteran who rode his Harley-Davidson here from Michigan.
Concerned particularly by the high suicide rate among veterans -- some 20 take their own lives every day, according to US statistics -- Vaillancourt says "the government is not doing enough to understand the mess that is in the head" of some veterans.
Many of the bikers, such as 58-year-old marine veteran Cecil Dorriety from South Carolina, seem to support the new administration of President Donald Trump.
"We need more support for the veterans. Hopefully it will come with the new administration," said Dorriety, who rode his Harley-Davidson here.
The parade, which thunders so loudly that it shakes buildings along its route, also attracts cycling enthusiasts drawn to a chance to take part in the good-natured demonstration.
Olivier Le Ber, a 54-year-old French expatriate living in Washington, has been a Rolling Thunder participant for years, along with family members on their own Harley-Davidsons.
He says he appreciates the "patriotic homage" and the sense of "brotherhood and solidarity" it creates.
Rolling Thunder gives people a chance "to meet other people one would normally never talk to."