Photos: US observes Memorial Day

Memorial Day
1 A US veteran of the Vietnam war visits the Vietnam Veterans' Memorial in Washington on May 23. 
Memorial Day
2 A bouquet of flowers at the Vietnam Veterans' Memorial on May 23. 
Memorial Day cemetery flags
3 Soldiers from the 3rd US Infantry Regiment, 'The Old Guard,' place flags at grave sites at Arlington National Cemetery in Arlington, Virginia. 
US Memorial Day cemetery flags
4 A small US flag was placed one foot in front of more than 220,000 graves in Arlington National Cemetery to mark Memorial Day. 
Memorial Day cemetery flags
5 Placing flags during the 'Flags-In' ceremony at Arlington National Cemetery. 
Bikers take part in the annual Rolling Thunder
6 Bikers take part in the annual Rolling Thunder ride in Washington, DC on May 25. 
Rolling Thunder
7 Bikers with banners ride in front of the US Capito. 
President Obama
8 US President Barack Obama does a Hawaiian "shaka" as he greets US troops during a surprise visit to Bagram Air Field, north of Kabul, in Afghanistan, May 25, 2014, prior to the Memorial Day holiday. 
Brad Paisley sings to US troops
9 Singer Brad Paisley performs for US troops during a surprise visit by President Barack Obama to Bagram Air Field, north of Kabul, in Afghanistan, May 25. 
Brad Paisley greets US troops
10 Singer Brad Paisley greets US troops. 
Obama in Afghanistan for Memorial Day
11 Obama greets US troops. 
Arlington scenes
12 Leesa Philippon of West Hartford, Connecticut, decorates the grave site of her son, U.S. Marine Corps Lance Corporal Lawrence Robert Philippon, at the Arlington National Cemetery. 
Arlington scenes
13 Sarah Greene of Branford, Connecticut, wipes tears as she visits the grave site of her husband, U.S. Marine Corps Lieutenant Colonel David S. Greene who was killed in 2004 in Iraq. 
On Boston Common
14 Volunteer Shannon Day of Boston helps to inspect some of the 37,000 flags at the Boston Common, Wednesday, May 22, 2014, in memory of Massachusetts soldiers killed in the line of duty since the Sept. 11, 2001, terrorist attacks. The display is part of a larger project to honor every fallen service member from the Revolutionary War to the present. The flags will be on display throughout Memorial Day weekend. 
State Veterans Cemetery in Little Falls
15 Raymond Flicek, 92, who served in the army from 1943-45 as a reconnaissance man, paid his respects to his wife Etta at the State Veterans Cemetery in LIttle Falls, Minn. 
Memorial Day
16 The procession at Fort Snelling National Cemetery, Minnesota, on Memorial Day. 
Memorial Rifle Guard
17 Members of the Memorial Rifle Guard at Fort Snelling National Cemetery on Memorial Day, 
Kevin Correia
18 Minnesota Twins pitcher Kevin Correia throws against the Texas Rangers in the first inning on Memorial Day in Minneapolis. Both teams wore military camouflage-themed hats and lettering to honor fallen troops.