Mary Duke Biddle, daughter of Benjamin Newton Duke, cofounder of the American Tobacco Company and the original buyer of the house at 1009 5th Ave in New York City, remembers growing up across from the Metropolitan Museum of Art. The Duke Semans Mansion, a 20,000squarefoot BeauxArts residence, On a Fifth Avenue block where all the other singlefamily residences have long since been torn down and replaced by apartment buildings, the Duke Semans Mansion, for which the family fought to get landmark designation, stands as a bulwark against modern development. With its high ceilings, goldleaf trimmed fixtures and intricate plaster friezes, the property is a living piece of architectural history.