5. The Cornelius Vanderbilt II Mansion, 742-748 Fifth Avenue
Cornelius Vanderbilt II’s mansion was allegedly the largest single-family house in New York City at the time. The son of the Commodore built this massive abode on the site of three demolished brownstones at the corner of 57th Street and 5th Avenue. It was designed by George B. Post and expanded by Richard Morris Hunt in the 1890s. As the development of Fith Avenue increased in the 1920s, the home became surrounded by commercial buildings, like the Plaza Hotel. The mansion was sold in 1926 and demolished to make way for the Bergdorf Goodman department store. Remnants of the mansion, including the front gates that are now in Central Park, sculptural reliefs now in the Sherry-Netherland Hotel, and a grand fireplace now in the Metropolitan Museum of Art, can be found throughout Manhattan!