Residence 5AB at 18 East 77th Street Perfectly positioned on one of the most coveted blocks on the Upper East Side, between Fifth and Madison Avenues and directly across from The Mark Hotel, Residence 5AB at 18 East 77th Street is an exceptionally rare 3-bedroom, 3.5-bathroom duplex penthouse with an impressive private terrace offering open views toward Central Park. Set within an intimate limestone-clad townhouse co-operative, the home offers a rare combination of classic pre-war character, townhouse-like privacy, and effortless indoor-outdoor living just off Central Park. The residence has a distinctly European sensibility, with gracious proportions, traditional detailing, and a warm, layered atmosphere throughout. The lower level opens through a central entry hall with tiled floors and a powder room. A spacious formal living room is anchored by a wood-burning fireplace, while French doors open to a skylit dining room wrapped in designer wallpaper. The windowed kitchen features a skylight, black marble floors, granite countertops, custom cabinetry, and stainless steel appliances. The primary suite is beautifully scaled and serene, with herringbone floors, a wood-burning fireplace, custom built-ins, three reach-in closets, and a charming window bench. The primary bathroom is finished with marble tilework, a pedestal sink, and a glass-enclosed rainfall shower. Two additional bedrooms offer flexibility for guests, family, or work-from-home needs, including a bedroom suite with two exposures and a windowed en-suite bath. Additional spaces on the lower level include a full bathroom, washer and dryer, den, and study, allowing for multiple configurations including a library, nursery, media room, or home office. The upper level is what makes the home truly special. A sun-filled lounge with custom built-ins and a butler's kitchen opens through three sets of French doors onto an expansive private terrace. Framed by lush planters and open exposures, the terrace offers exceptional space for outdoor dining, lounging, and entertaining, with views toward Central Park and the surrounding Upper East Side skyline. 18 East 77th Street is a discreet and elegant townhouse co-operative with an elevator, video intercom, and just five residences. The location is among the best in Manhattan, moments from Central Park, The Met, Museum Mile, Madison Avenue shopping, The Mark, The Carlyle, the Frick Collection, renowned restaurants, galleries, cafés, and neighborhood staples including Citarella, Butterfield Market, Eli's, and D'Agostino. A rare duplex penthouse combining the character and privacy of townhouse living with the convenience of a co-operative residence, all in one of the Upper East Side's most desirable locations.