I think = Mar-a-lago is the only one on the list besides #1 Buckingham Palace at $4.9 billion that has "any formal military bunker capabilities" and therefor should be assess closer to number 1 than all the rest. So when you couple that with knowing the future "Trump Branding" == would increase it's valuation exponentially as part of our society let alone our history due his Presidency; we are left with a value proposition equal too or beyond that of Buckingham Palace.