Hundreds of thousands of men and women rolled into Washington, D.C., on motorcycles Sunday morning as part of an annual Memorial Day tradition that honors fallen service members.

"Fantastic to have 400,000 GREAT MEN & WOMEN of Rolling Thunder in D.C. showing their patriotism. They love our Country, they love our Flag,

they stand for our National Anthem! Thanks to Executive Director Artie Muller," Trump tweeted Sunday.



Fantastic to have 400,000 GREAT MEN & WOMEN of Rolling Thunder in D.C. showing their patriotism. They love our Country, they love our Flag, they stand for our National Anthem! Thanks to Executive Director Artie Muller. — Donald J. Trump (@realDonaldTrump) May 27, 2018



Sunday marked the 31st year people have gathered from all over the country on Memorial Day weekend to ride and remember members of the military who made the ultimate sacrifice.

The group gathers at the Pentagon around noon then departs for a lap around the National Mall, which includes the Lincoln Memorial, Vietnam Memorial, Reflecting Pool, Washington Monument, U.S. Capitol, Thomas Jefferson Memorial, Tidal Basin, and Korean War Memorial.



Thousands of bikes now leaving Fairfax City. Keep it with @WTOP for the story and the impact on major highways pic.twitter.com/kDX89TNnAr — John Domen (@JDDsays) May 27, 2018



Spectators can always hear the hundreds of thousands of bikers approaching before being able to see them.

Most bikers carry full or mini American, POW, MIA, or other military flags on the backs of their vehicles.





The organization's announcement of the 2018 event states the ride will go "through Washington, D.C., to the Vietnam Veterans Memorial to pay our respect to our brothers and sisters who gave their lives for the freedom we enjoy every day and for the full accounting of all POWs-MIAs and veterans rights. This is a demonstration - not a parade."

Rolling Thunder lists prisoners of war and missing in action from wars in the 1910s through the 1960s, including 3,344 in World War I; 78,184 in World War II; 7,687 in Korea; and 1,607 in Vietnam.



There is a sea of awesome at the Pentagon! #RollingThunder pic.twitter.com/pyqh4dPyxB — InsideThaDugout (@InsideThaDugout) May 27, 2018



Days ahead of the Sunday event, some bikers kick off their journey in California make their way east to Washington, picking up members from different states along the way.

The ride Sunday is followed by a speaker and concert near the Lincoln Memorial.