The Vanderbilt Mansion at Hyde Park, NY. Built by the third generation of Vanderbilt millionaires, this neoclassic style mansion was completed in 1899. Long accustomed to wealth, Frederick Vanderbilt had his home designed by the best architects in New York, and furnished it in fabulous artifacts from abroad mixed with period reproductions. The estate, inside and out, offers a great perspective of the wealth and excess of the Gilded Age and one of its most prominent families.