A one-of-a-kind Duplex on Park Avenue has hit the market for the first time since 1930. The residence, which is located at 784 Park Avenue, was previously owned by noted philanthropists Stephen and Anna-Maria Kellen and is the epitome of pre-war elegance. The home spans 2 floors with over 14 rooms in total with 5 bedrooms, 4 of which are en-suite. Details including a marble-floored entrance gallery, salon with wood-burning fireplace, grand staircase, library, formal dining room, eat-in kitchen with double exposure views, and a massive outdoor balcony. 784 Park Avenue was designed by renowned NYC architecture firm Emery Roth & Sons and built in 1930. The full-service, white-glove building offers a full-time doorman, manned elevator, gym, resident super, playground, storage, and a bike room. 784 Park Avenue Apartment 16/17C is currently listed for $14.995 million with Claire Groome of Warburg Realty and Barbara Evans-Butler of Stribling.