Marble House, a Gilded Age mansion located at 596 Bellevue Avenue in Newport, Rhode Island, was built from 1888 to 1892 as a summer cottage for Alva and William Kissam Vanderbilt and was designed by Richard Morris Hunt in the Beaux Arts style. It was unparalleled in opulence for an American house when it was completed in 1892.
The house was added to the National Register of Historic Places in 1971 and was designated a National Historic Landmark in 2006. It is now open to the public as a museum run by the Newport Preservation Society.
Wikipedia https://en.wikipedia.org/wiki/Marble_House
Official Website https://www.newportmansions.org/explore/marble-house
Coordinates 41°27'43.496" N -71°18'20.206" E