from the History Channel:

December 29, 1915
French government gives land for British war cemeteries
On this day in 1915, the French National Assembly passes a law formally ceding the land that holds the British war cemeteries to Great Britain. The move ensured even as the war was being fought that its saddest and most sacred monuments would be forever protected.

The law stated that the land was “the free gift of the French people for a perpetual resting place of those who are laid there.” By the end of the war, it would apply to more than 1,200 cemeteries along the Western Front, the majority located near the battlefields in the Somme, Nord, and Pas-de-Calais regions. The Commonwealth War Graves Commission, established in 1917 by a British royal charter, supervised the construction of the cemeteries and their monuments, which were designed by some of the most prominent British architects of the day. The last monument was put in place in 1938.

The French office of the commission is charged with the maintenance of these cemeteries; between 400 and 500 members of its staff tend the graves and the surrounding horticulture. In addition to the cemeteries, the Commonwealth War Graves Commission also tends to the numerous monuments that exist on the Western Front to commemorate the missing. One of the largest of these stands at Thiepval, on the Somme battlefield, and bears the names of 73,357 British and South African soldiers and officers who died there between July 1915 and March 1918 and whose final resting place is not known.