I'm guessing that it's similar to our National Register of Historic Places. You might be the owner of a culturally significant property, but the government has seen fit to restrict some of what you can do with it based on a perceived importance of preserving it.
I have mixed feelings on the matter. Generally, I'm a strong believer in private property rights, but I think there is value in having the means in place to prevent say, the Mount Vernon's Ladies Association from selling the property to Chinese investors who were looking to develop high rise apartments on the grounds.
(Sigh. The Daily Mail needs to get rid of its demand that I drop my ad blocker...)
With historic sites in the US, people give up rights when they take government money to maintain them. If someone hasn’t taken the money, let them do as they will. The further this country strays from its history, the less significant many of those sites would be.