The Unknown Warrior, Memorial tomb in Westminster Abbey, United Kingdom.

The Unknown Warrior is a rectangular slab of polished black Belgian marble set into the floor of Westminster Abbey, inscribed in gold capitals and bordered by a frame of red artificial poppies. It lies at the far western end of the nave, a few feet from the west door, and is the only gravestone in the abbey that visitors are not allowed to walk on.

The idea came from chaplain David Railton in 1916, and in 1920 Brigadier L. J. Wyatt chose one of four flag-draped coffins at Saint-Pol-sur-Ternoise by resting his hand on it. The casket crossed to Dover on HMS Verdun and was buried in the abbey nave on 11 November 1920, the same day France interred its unknown soldier.

The stone serves as a place where visitors pause to remember those who fell without name or known grave. Many people leave flowers or stand in silence as a mark of respect for all unidentified servicemen.

The stone lies in the main walkway through the nave and is easy to spot as you enter through the west door. A barrier keeps visitors from stepping directly on it, so you can view the inscription from a short distance.

The United States awarded its Medal of Honor to this British soldier in 1921, a rare gesture for a foreign serviceman. No one, not even members of the royal family, is allowed to walk over the stone.