In a class of its own, this magnificent Duplex Penthouse redefines luxury living, offering an unparalleled layout, spectacular views, and generous outdoor space. Perfectly positioned on the top two floors of 520 Park Avenue, the most distinguished boutique condominium on the Upper East Side, this home is akin to a grand townhouse in the sky. Enjoy dazzling panoramic views from all four exposures, throughout the home's five bedrooms, six full bathrooms, two powder rooms, and vast entertaining spaces including a one-of-a-kind Solarium. The story of this brand-new 8,310 square foot home begins at the private key-locked elevator landing on the 63rd floor, which leads to the vast double height entrance gallery with expansive art walls and custom staircase. All of the entertaining spaces flow from the gallery, starting with the formal dining room featuring two double-wide doors leading to the 279 square foot balcony. Spanning nearly 42' long, the balcony expands the dining room and kitchen into indoor-outdoor living spaces perched high above the Upper East Side. The dining space leads seamlessly into the exquisite corner living room encompassing the North-East corner of the home, featuring breathtaking views of Central Park, the city skyline, both the Hudson and East Rivers and much more through the oversized bay windows. Adjacent to the living room is a library with corner windows, fireplace with statuary marble surround, and wet bar.The windowed eat-in-kitchen exquisitely outfitted in custom floor-to-ceiling Christopher Peacock cabinetry designed by Robert A.M. Stern features hand painted cabinets with hand-blown glass. The Covelano Oro marble-clad island with a vented hood anchors the kitchen which includes a first-class appliance package by Sub Zero, Miele and Wolf.Ascending the custom staircase, one enters the unprecedented Solarium. The expanse of this glass enclosed space offers a magical reprieve from the city below. With soaring ceiling heights, floor-to-ceiling glass walls, and three access points to the terraces totaling 849 square feet of outdoor space, this room encompassed year round indoor-outdoor living and entertaining. The onyx-clad powder room and custom wet bar with refrigerator, ice maker, dishwasher and sink, round out the offerings in the 64th floor gallery.With private access from the Solarium or main entrance from the gallery, the massive primary bedroom suite encompasses the entire Northern side of the 64th floor, offering jaw dropping views of Central Park and beyond. The suite includes two private dressing areas and two luxurious windowed bathrooms outfitted with steam showers, radiant heat flooring, beautiful marble slabs, polished nickel Dornbracht fixtures, custom-designed vanities, and a freestanding soaking tub with incredible park-facing views. A private entrance to the Northern terrace directly from the primary bedroom allows for the perfect setting to enjoy one's morning coffee al fresco.With two secondary bedroom suites located on the lower level and two secondary bedroom suites located on the upper level, the inspired layout allows for the utmost privacy throughout the home. All secondary bedroom suites feature expansive southern views, an abundance of closet space, and en-suite windowed marble bathrooms with Dornbracht fixtures and custom vanities designed by Robert A.M. Stern. The windowed laundry room features custom millwork, Kohler sink, two washing machines and two vented dryers by Electrolux.This Duplex Penthouse features tremendous proportions, being the only residence in the building to offer 15 foot ceiling heights on both the upper and lower levels. Key features include a private interior elevator, select-cut solid white oak hardwood flooring in classic herringbone and overlay patterns, custom crown molding throughout, custom applied wall moldings in the gallery, and multi-zone central air conditioning and heating with precise temperature c