Riders flew flags of many colors in addition to the Stars and Stripes during during Rolling Thunder XXXI First Amendment Demonstration Run in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
Air Force veteran Ray Weaver from Lancaster, Penn., gives his traditional salute on Sunday, May 27, to riders in the Rolling Thunder motorcycle procession on Memorial Day in Washington, D.C.(Ben Murray/Military Times)
Salute to the riders during Rolling Thunder XXXI First Amendment Demonstration Run after they passed the Lincoln Memorial in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
Riders in the Rolling Thunder Memorial Day motorcycle procession ride across the Memorial Bridge, with Arlington National Cemetery in the background as they enter Washington, D.C. on Sunday, May 27, as part of the annual remembrance festivities in the city. (Ben Murray / Military Times)
Riders circle around the back of the Lincoln Memorial with the Air Force Memorial in the backgroundduring Rolling Thunder XXXI First Amendment Demonstration Run in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
An onlooker looks at wreaths in the Korean War Memorial on Sunday, May 27 in Washington, D.C. during Memorial Day Weekend festivities throughout the city. (Ben Murray / Military Times)
Navy veterans and brothers Mark, left, and John Brancaccio, right, salute riders as they pass them along Constitution Ave during Rolling Thunder XXXI First Amendment Demonstration Run in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
Riders in the Rolling Thunder Memorial Day motorcycle procession ride through the capital in Washington, D.C. on Sunday, May 27, as part of the annual remembrance festivities in the city. (Ben Murray / Military Times)
Pedestrians walk through the Korean War Memorial on Sunday, May 27 in Washington, D.C. during Memorial Day Weekend festivities throughout the city. (Ben Murray / Military Times)
An onlooker looks at wreaths in the Korean War Memorial on Sunday, May 27 in Washington, D.C. during Memorial Day Weekend festivities throughout the city. (Ben Murray / Military Times)
Riders in the Rolling Thunder Memorial Day motorcycle procession ride through the capital in Washington, D.C. on Sunday, May 27, as part of the annual remembrance festivities in the city. (Ben Murray / Military Times)
Susan McBride, from Maryland, thanks riders for their service during Rolling Thunder XXXI First Amendment Demonstration Run along Constitution Ave. in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
Air Force veteran Anna Sanders from Baton Rouge, LA, shows her support to riders during Rolling Thunder XXXI First Amendment Demonstration Run along Constitution Ave. in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
A rider slaps hands with some of the supporters who came out to line the route along Constitution Ave. during Rolling Thunder XXXI First Amendment Demonstration Run in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
Riders wave to the large crowd during Rolling Thunder XXXI First Amendment Demonstration Run along Constitution Ave. in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
Spectators waved to riders during the Rolling Thunder XXXI First Amendment Demonstration Run along Constitution Ave. in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
Park Police officers wave to riders as they pass them during Rolling Thunder XXXI First Amendment Demonstration Run along Independence Ave. in Washington, DC on Sunday May 27, 2018. Motorcycle riders from across the nation, rode a designated route through the Mall area of Washington, D.C. The event is an actual demonstration/protest to bring awareness and accountability for POWs and MIAs left behind.(Alan Lessig/Staff)
Retired Master Gunnery Sgt. Johnny Herrmann welcomes fellow riders to Rolling Thunder.