Near me is the Biltmore Esate - a historic house. Old by US standards (barely broken in by British standards). 176,000 square feet (something like 3 nautical kilotons in metric), created by George Vanderbilt. I first took a tour there when I was about 10. Since then, they've added plexiglas "no touchie!" barriers to protect curtains, walls, books, and other things we used to be able to walk near, because too many people were touching them, and the repairs are expensive (wallpaper has to be custom made in France to match what was there).