One of Carnegie Hill's most storied and rare 40-foot-wide mansions, 12 East 94th Street is a singular urban residence. This 15,235-square-foot, five-story landmark possesses extraordinary provenance, architectural distinction, and cultural gravity. Originally designed by A. B. Ogden & Son for developer John H. Gray as part of a distinguished row of brownstone-faced houses, 12 East 94th Street was subsequently renovated and reimagined in its entirety by Rafael Viñoly -- elevating every detail to museum quality. The five-bedroom home's renovation marries the gravity of the original 19th-century townhouse with a sculptural modernism grounded by an iconic curved central stairwell and garden curtain wall -- the latter a defining gesture of transparency rare on the Upper East Side -- a unique oasis in the heart of the city. The first floor of the house served as the home of Salon 94, the contemporary art gallery founded by Jeanne Greenberg Rohatyn, lending the residence cultural biography. The Viñoly renovation was conceived to accommodate both the private and the monumental -- a distinction that informs every room. Entry is announced by an impressive burr walnut veneer door of commanding scale and craftsmanship. Beyond it, the first floor unfolds as a dedicated salon -- with an adjoining library office, powder room, and generous walk-in coat closet. The vast living room gallery, with Viñoly's signature curved glass facade, gives way to a tranquil modern garden below, while a self-contained guest suite with kitchenette offers complete privacy. At the heart of the residence rises Viñoly's defining gesture: a continuous sculptural staircase clad in burr walnut veneer -- matching the entry door in a considered act of material continuity -- spiraling upward through all four floors to a crowning skylight that floods the interior with natural light. On the parlor level, an expansive formal living room with elegant curved ceilings of exceptional height, designed for the display of art, and a dining room seating 16. Both rooms have working wood-burning fireplaces and are separated by an elegant landing and large pocket doors -- a gracious arrangement designed for grand entertaining and equally suited to an intimate evening at home. The windowed eat-in chef's kitchen features custom banquette seating, a full suite of Wolf and Sub-Zero appliances, and a bespoke floor-to-ceiling climate-controlled wine cellar -- a rarity of both design and function. Family bedrooms are gathered on the third floor. An expansive primary suite overlooks the garden, centered on a grand walk-in closet and a large windowed ensuite with a double shower and soaking tub. Separated by a landing, two additional large bedrooms -- each with ample closet space and a private ensuite bath -- complete this level with quiet comfort and discretion. The top floor offers remarkable versatility: a fitness room, a yoga room, a fourth bedroom with ensuite, an immersive media room, and a generous study that crowns the residence in scholarly calm. Proportions and light on this level rival the floors below -- a rare achievement in townhouse architecture. The grand finale is a phenomenal private rooftop terrace. With open sky above Carnegie Hill, it is among the most coveted private outdoor spaces on the Upper East Side. The basement contains a fully equipped laundry room and a live-in staff apartment. Co-Exclusive with Modlin Group. 12 East 94th Street is not merely a residence -- it is an argument for how one should live.