Arlington National Cemetery

President Bush leads the United States Memorial Day observances Monday at Arlington National Cemetery, near Washington, with a ceremony honoring U.S. war veterans.

Mr. Bush will lay a wreath at the cemetery and deliver a speech, as the nation pauses to honor the service and sacrifice of the men and women of the U.S. armed services. Memorial Day is a national holiday, and many other ceremonies are taking place in Washington and across the country.

Thousands of motorcycle riders from across the United States rallied in Washington Sunday for their annual tribute to military veterans.

'Rolling Thunder' bikers cross the Memorial Bridge, from Virginia, to Washington, DC

The "Rolling Thunder" rally, named for the thunderous noise of thousands of motorcycle drivers' engines is intended to focus attention on veterans' health concerns, and the continuing effort to trace American soldiers missing in action, from the Vietnam War and other conflicts.

The bikers, many of them veterans of the Vietnam war, gathered at the Pentagon, then rode in formation past the Vietnam Veterans Memorial near the White House.

Arlington National Cemetery, where President Bush will speak, lies across the Potomac River from the Lincoln Memorial and other national monuments honoring veterans of the Second World War, the Korean War and the Vietnam War.

The cemetery holds the remains of more than 300,000 Americans - members of the military services from conflicts dating back to the American Civil War, nearly 150 years ago; two U.S. presidents, including John F. Kennedy, who was assassinated in 1963; and many other prominent Americans. A relatively new section of the cemetery holds the graves of nearly 350 men and women killed in Iraq and Afghanistan - nearly one in 10 of the American victims of those conflicts.

Some information for this report was provided by AP and Reuters.