Wondrous details abound in this one-of-a-kind mansion, anchored by a majestic rotunda lined with a spiral filigree staircase and crowned with a glass dome. Other highlights include a classic Georgian-style faade, a central elevator, stunning parquet de Versailles hardwood floors, scagliola trims, concave custom designed doors, bullet-proof windows, dual professional kitchens, staff facilities, a dining terrace, and an incredible upper level deck–an enormous entertaining space that enjoys awe-inspiring views of the New York City skyline, bridges, and the East River. On the parlor floor of the house, residents enter the impressive vestibule with soaring double-height ceilings, flanked to the left and right by two doors: the left leads to the service wing while the right leads to a second direct entry to the grand salon. Straight through, one finds an elevator, a guest powder room, then a majestic rotunda. Formal living and dining spaces sit on either side of this elegant receiving room. Expansive and bright, the double-width salon possesses dual gas fireplaces and bay windows that bathes the room with warm morning light. The dining room has an attached alfresco terrace and provides easy access to the China Room, and the proceeding breakfast room with serving kitchen that connects to a commercial-grade kitchen one floor below. Food can also be transported through a dumbwaiter that connects both. The second floor contains two guest bedrooms with ample closets and pristine en-suite marble bathrooms. Opposite is a multi-room library clad in handsome custom oak paneling and multiple shelves with built-in lighting throughout. The study has a powder room en-suite. The primary suite occupies the entire third floor. The 33-ft wide bedroom has a fireplace and large bay windows with a splendid view of the garden and the East River. The remainder of the suite is made up of a wardrobe corridor, a bedroom-size windowed dressing room, a drawing room with an attached terrace and powder room, and a sublime en-suite onyx bathroom with double sinks, a walk-in shower, an enclosed water closet, and a deep soaking tub. The rooftop terrace has a grill, an enclosed solarium-style wet bar, a powder room, and open city and river views. The lower level boasts a fitness room, which can easily be reverted into a bedroom if one chooses, and an adjacent second bedroom with bath en-suite. Right outside is a Japanese bath equipped with an ofuro (soaking tub). Towards the western end of the house is a service entrance, wine closets, a commercial-grade kitchen equipped with three sinks, multiple refrigerators and walk-in freezers, and double ovens and stoves, commercial dishwashers, and multiple cabinets and storage spaces. A laundry room, a staff lounge, and two powder rooms complete this level. Situated in the secluded Sutton Place enclave, 7 Sutton Square is moments from restaurants, bars, cafes, and shops. Sutton East Tennis Club is a few blocks away, and Park, Madison, and Fifth Avenues are all close by.