You have to understand that this is a huge house, built just over 100 years ago, in the south, without air conditioning. It was a winter home for the Vanderbilts, who spent the summers in New York and Rhode Island.
It's over 175,000 square feet. The family only used it for about 35 years before they started using it as a tourist attraction. I don't know if the Vanderbilts expected to become new royalty, but they had the estates for it, until 1930.
We found the servants' quarters especially interesting. The self-guided tours are routed in such a way that it's hard to imagine living or visiting in the house. But it's very interesting and the sort of thing we should all see at least once.