As a historian I am always appalled when ancient monuments are destroyed, but there is a long history of religiously motivated destruction of predecessor religions. There are different reasons, but often it is in the name of purifying the land of religious contaminants. When I was in England visiting cathedrals I saw examples of efforts to deface monuments in the name of the Reformation. In recent years we have witnessed efforts by the Taliban and now ISIS destroy priceless historical sites. In part, I think this is an expression of nihilism, but as Robert Cohn points out it can also be an expression of a fear of any future outside their own. It is sometimes difficult to complain about the destruction of historical sites when people suffer, but these historical sites are part of our human experience and expressions of human creativity. They need to be protected as well.