The United States is observing Veterans Day, a day to remember and celebrate those who have served in the country's military.

President Bush traveled Sunday from his ranch in Crawford, Texas, to the town of Waco where he addressed a group of veterans. Mr. Bush thanked the veterans for their service. He also noted the sacrifice of four Texans killed in the war on terror.

In Washington, many observed the day by visiting the Vietnam War Memorial, which was opened 25 years ago.

The memorial is a polished black granite wall engraved with the names of more than 58,000 members of the U.S. military killed during that conflict. It honors the 2.7 million Americans who served in Vietnam.

Vice President Dick Cheney paid tribute to veterans during a wreath-laying ceremony at Arlington National Cemetery just outside Washington.

Veterans Day was first celebrated in the United States in 1919, to honor those who served in World War One. It was then called Armistice Day, marking the truce that ended the war on November 11, 1918. The day is also marked by many other nations around the world, where it is known variously as Remembrance Day, Armistice Day and Veterans Day.