U.S. President Barack Obama salutes at the Tomb of the Unknowns at Arlington National Cemetery in Virginia.

U.S. President Barack Obama on Monday praised the men and women of America's fighting forces as the "best of America."

The president spoke after participating in a solemn Memorial Day tradition, laying a wreath at the Tomb of the Unknowns at the Arlington National Cemetery in Washington. It is the burial ground for American veterans dating back to the Revolutionary War.

Many Americans observe this holiday by visiting cemeteries and memorials. A national moment of remembrance took place at 3 p.m. local time. Another tradition is to fly the flag of the United States at half-staff from dawn until noon local time. Volunteers often place American flags on each grave site at National Cemeteries.

In addition to national observances, many individual communities hold memorial observance for fallen soldiers who were from that town by having a ceremony in a church or town memorial park.