Red sandstone was used to build this Norman fortress in 1855. Joseph Henry, the first Smithsonian Secretary, worked and lived there. Today, it houses the Smithsonian's visitor center.
In 1926, inventor and scientist John Hays Hammond ordered this English-inspired palace. He kept his Roman, medieval, and Renaissance items indoors.
America's largest private mansion is George Vanderbilt's 19th-century Blue Ridge Mountain estate. Biltmore Estate is a historic house museum with gardens, a winery, and a large library.
Designed by Dario Sattui, it looks like ancient Tuscany but was finished in 2007. The Napa Valley winery Castello di Amorosa is famous.
Many of the castle's 107 rooms are utilized for winemaking. The castle's ancient dungeon and drawbridge are open to visitors, along with superb wines.
Newspaper magnate William Randolph Hearst built Hearst Castle. Completed in 1947, "The Enchanted Hill" has four buildings and 165 rooms.
Hawaii's royal residence, Iolani Palace, was built by King Kalakaua in 1882. The palace is the first American Florentine (Italian Renaissance and Hawaiian architecture) building.