The Thiepval memorial was opened on 31 July 1932 by the Prince of Wales, and remains the largest British war memorial in the world.
The memorial contains the names of 73,357 British and South African men who have no known grave and who died or went missing on the Somme between July 1916 and 20 March 1918.
The 150ft high memorial was designed by Sir Edwin Lutyens.