In 1895 there were 300 live hummingbirds hovering around an indoor fountain in honor of the Duke of Marlborough's visit to Marble House built in Newport RI by William K. Vanderbilt, grandson of Commodore Vanderbilt.
Looking back at Manhattan's lost Gilded Age mansions
Cornelius Vanderbilt II mansion (demolished) formerly at 1 West St, New York City. Architects George B Post and Richard Morris Hunt. Built 1882 with substantial 1894 addition. Demolished Vintage b&w photo.
Chicago's Greatest Surviving Gilded Age Mansions, Mapped
Mansions of the Gilded Age: Estate of Nicholas Brady Inisfada, Manhasset, New York. It later became a Catholic retreat, but was torn down in 2013 to make way for luxury housing. I went here in grade for a retreat before my confirmation.