Travel over the Potomac to Arlington, Virginia to walk among the sober gardens and clean white gravestones in the 600-acre (242-ha) Arlington National Cemetery. Explore the reverent monuments and memorials of this hallowed ground on a convenient trolley that takes you to the cemetery's major sites.

The land that is now Arlington National Cemetery has played an important role throughout American history, serving as a camp for Federal Troops during the Civil War and as a safe haven for slaves entering the free North. It began to be used for military burials in 1864. Learn about some of the 400,000 heroes, presidents, and veterans buried here, and watch the somber Changing of the Guard at the Tomb of the Unknown Soldier.

You can move through the cemetery at your own pace, stepping off the trolley for a closer look at different stops which include:

• President John F. Kennedy Gravesite

• Tomb of the Unknown Soldier

• The Arlington House

Tomb of the Unknown Soldier Stop: The guard is changed every half hour from April 1 through September 30 at the top and bottom of the hour. The guard is changed every hour on the hour from October 1 through March 31.

Memorial Amphitheater, inside the Arlington House and Iwo Jima remain closed to the public.