The headstone of Army Christopher William Swanson is seen at Arlington National Cemetery on Memorial Day in Arlington, Va., Monday, May 31, 2021. (AP Photo/Jose Luis Magana)

CORRECTS YEAR A U.S. Marine Corps, who wants to remain anonymous, honors veterans graves at the Los Angeles National Cemetery in Los Angeles, Monday, May 31, 2021. He has placed American flags for the last 15-years, first as a boy scout, this year as a U.S. Marine. Authorities said a giant American flag and several smaller flags were stolen from a Southern California veterans cemetery over the Memorial Day weekend. Les' Melnyk, a spokesperson for the Department of Veterans Affairs National Cemetery Administration, said the garrison flag at Los Angeles National Cemetery was reported stolen sometime late Sunday or early Monday. (AP Photo/Damian Dovarganes)

Boston Red Sox's Marwin Gonzalez pauses during a moment of silence in honor of Memorial Day before a baseball game against the Houston Astros Monday, May 31, 2021, in Houston. (AP Photo/David J. Phillip)

President Joe Biden salutes as Secretary of Defense Lloyd Austin places his hand over heart during the playing of "Taps," during the National Memorial Day Observance at the Memorial Amphitheater in Arlington National Cemetery, Monday, May 31, 2021, in Arlington, Va.(AP Photo/Alex Brandon)

Andrew Weston touches the gravestone of his uncle, U.S. Army Vietnam war veteran Thomas Shaun Monahan, at the Abraham Lincoln National Cemetery on Memorial Day, Monday, May 31, 2021 in Elwood, Ill. (AP Photo/Shafkat Anowar)

The Field of Heroes at Centennial Park across from Tulsa VFW Post 577 Monday, May 31, 2021 in Tulsa, Okla. The field contains empty boots to give a visual representation of Oklahoma's fallen service members. (Mike Simons/Tulsa World via AP)

Military service members toast over the grave of a fallen soldier at Arlington National Cemetery on Memorial Day in Arlington, Va., Monday, May 31, 2021. (AP Photo/Jose Luis Magana)

President Joe Biden makes the sign of the cross as he places a wreath at the Tomb of the Unknown Soldier at Arlington National Cemetery on Memorial Day, Monday, May 31, 2021, in Arlington, Va.(AP Photo/Alex Brandon)

Boston Red Sox's Marwin Gonzalez pauses during a moment of silence in honor of Memorial Day before a baseball game against the Houston Astros, Monday, May 31, 2021, in Houston. (AP Photo/David J. Phillip)