The Thiepval Memorial to the Missing of the Somme is the largest Commonwealth memorial anywhere in the world and is dedicated to the 72,254 British and South African men who died in the Somme battles between 1915 and 1918 and have no known grave. Designed by Sir Edwin Lutyens it sits on the ridge above the River Ancre and dominates the battlefield for miles around. The design was an adaptation of a memorial originally intended for St Quentin. By the time building began in 1928, French sensitivities about the number and scale of British monuments on the Western Front forced Sir Edwin to reduce the height of his original conception to bring it below the height of the Arc de Triumphe in Paris. The Thiepval Memorial was unveiled on 1 August 1932 by the Prince of Wales (see photographs below). At the base of the memorial is a cemetery with 300 Commonwealth and 300 French graves to signify the joint nature of the 1916 offensive and as a further gesture to mollify the French. The dead of other Commonwealth countries, who died on the Somme and have no known graves, are commemorated on national memorials elsewhere. There is now an excellent visitor centre close to the memorial which opened in 2004. In 2016 Princes Charles, William and Harry attended a service of commemoration at Thiepval to mark 100 years since the first Somme battle began. The memorial has been completely renovated by the Commonwealth War Graves Commission with a new internal drainage system, repointing of some of the brickwork and the panels cleaned or replaced.