I don't think it's obvious what it means to preserve historical works. A really clear example of my point is the Cerne Abbas Giant, a chalk figure on a hill in

I don't think it's obvious what it means to preserve historical works. A really clear example of my point is the Cerne Abbas Giant, a chalk figure on a hill in England. For a long time the idea was to try to leave it untouched. Adding chalk was seen as something like touching up the mona Lisa. But it was in danger of being lost and if memory serves it was discovered that when it was made people would refresh the chalk regularly. It's inherent to the work that it is maintained. Let's say this giant is at one end of the spectrum, and the Mona Lisa is at the other. Its subjective where you place cathedrals, but certainly the builders intended it to be an operational building, and throughout its history there have been additions and modifications.