The Shrine at Mametz / Somme 1916

[George87]

Does anyone know about the history of the Shrine mausoleum at Mametz being destroyed and rebuilt?

I was surprised to see reinforced concrete with steel rods in the foundations / base when visiting on the weekend - i.e. what you would expect from a wartime pill box / concrete emplacement - when the mausoleum itself is obviously civilian, ornate and in a style that looks to pre-date the war in appearance. 

Presumably it pre-existed 1916 and was reinforced by the Germans during the war, destroyed in the fighting and then rebuilt in the original civilian style on top of the war time reinforced base after the war?

Many thanks