Please note that the graves in Germany are not perpetual. After a certain period of repose (20-30 years) the graves are being leveled and re-used. There is no toxic embalming being done in Germany, so the coffin and the corpse have decomposed naturally. If the family of the deceased decides to purchase another period the duration can be extended by another 30 years. War Graves are considered memorials and are kept up by the owner of the cemetery. Those are kept forever.