Over 90% of these were killed between July 1 and November 4, 1916 during the Battle of The Somme.  Their bodies were either lost forever or were found when the battlefields were cleared by which time all trace of their identity had disappeared.

The Memorial to the Missing is considered to be one of the greatest monuments in the north of France.  It was designed by Sir Edward Lutyens and is built of brick with stone detailing. 

The Memorial to the Missing stands 141 feet high and comprises sixteen piers on which the names of the missing are inscribed. 

To give the memorial stability in an area riddled with tunnels dug during the fighting, it stands on a concrete raft 10 feet thick buried 19 feet below ground. 

The Memorial to the Missing was unveiled by the Prince of Wales on July 31, 1932 in the presence of the President of the French Republic.

Every time the remains of a soldier named on the memorial are found and identified, he is given a full military funeral.  His name is also erased from the memorial, as he is no longer missing.  This is why there appears to be gaps in the lists of names.

Vincent Scully, in his Architecture: The Natural and the Manmade (1991), describes the memorial geography of this landscape with monument and graves:

Aut"Again, a great work of architecture . . . helps us perceive the character of one major part of that threat, the evil, empty face of war.  North of Amiens the land rises slowly in rolling open fields leading toward the heights of the Somme.  There Lutyens built a memorial to the hundreds of thousands of British and French soldiers who were killed in this landscape, literally for nothing, throughout the summer of 1916.  They were heading for the high ground.  We follow their track across the open fields.  The memorial looms indistinctly far ahead of us on the height.  We move toward it.  There is no cover.  We imagine the machine guns sweeping the gentle slopes.  We turn toward the little folds in the earth that open to left and right of the road and seem to offer refuge from that fire; it is apparent that the infantry did exactly that before us.  They are still there in many of the defilades, laid out neatly in small cemeteries where the artillery and the mortars found them.  We arrive at the height, the objective."

The Memorial to the Missing is situated south west of Thiepval on the road to Authuille