President Bush laid a wreath at Arlington Cemetery's Tomb of the Unknowns for one last time on Memorial Day.

His successor inherits that duty next year.

In his last Memorial Day Proclamation, Bush said that America's freedoms "come at great costs."

But he added that the brave men and women who have fought and died in the nation's service have "transformed the world in unimaginable ways."

The president was also calling on Americans to observe a "moment of remembrance" at 3 p.m. local time to honor those who have perished fighting for freedom.

Heeding the president's request, the moment will be observed by Major League Baseball. Amtrak trains will all sound their horns, and buglers will play taps at military cemeteries.