WATCH: Centennial commemoration of the Tomb of the Unknown Soldier

Arlington National Cemetery opened the Tomb of the Unknown Soldier Plaza Tuesday to allow the public to walk on and lay flowers in front of the Tomb, for the first time in nearly 100 years.

Watch the ceremony in the player above.

The Tuesday opening began with representatives from the Crow Nation placing flowers at the Tomb and reciting a prayer that may have been given 100 years ago by American Indian Chief Plenty Coups and ends Wednesday with the original benediction recited by the Army Chief of Chaplains Maj. Gen. Thomas L. Solhjem.

The public ceremony is part of several events to mark 100 years since the funeral for the unknown soldier on Nov. 11, 1921.

The unidentified remains of a World War I soldier were carried in a horse-drawn wagon through Washington, D.C., across the Potomac River, and into Arlington National Cemetery.

The tomb now includes the remains of soldiers from World War II and the Korean War.

In the past 100 years, the tomb has become a symbol of American service and sacrifice, as well as a place for mourning and reflection that attracts millions of visitors every year according to officials.

Typically access to the plaza and the tomb is only given to the 3rd U.S. Infantry Regiment, known as “The Old Guard,” which is designated to watch over the Unknown Soldier twenty-four hours a day.

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