occupying a prominent corner within the landmarked o'neill building, penthouse b is a premier duplex residence that balances gilded age scale with contemporary architectural precision. originally constructed in 1887 as a premier department store in the ladies' mile historic district, the building was reimagined into a collection of luxury residences that retain the soaring volumes of its cast-iron heritage. this trophy home spans 4,819 square feet of interior space, complemented by a triple-terrace outdoor program totaling over 2,500 square feet. the great room serves as the residence's focal point, spanning 53 feet in length and framed by over 220 linear feet of windows. high ceilings and a dual southern and eastern exposure provide superlative natural light and panoramic views of the manhattan skyline. the layout is currently configured as a three-bedroom home but was originally designed for four true bedrooms, allowing for significant flexibility in how the space is utilized. a signature element of the property is the historic gold-coated neo-grec cupola. one of only a handful remaining in new york, this 43-foot high belfry can be converted into a private media room or home office, offering a 360-degree architectural experience. the kitchen is designed for high-capacity entertaining, featuring a large center island, viking and sub-zero appliances, a butler's pantry, and a separate breakfast room. the upper level is dedicated to the primary suite, providing a secluded sanctuary with an oversized spa bath and two walk-in dressing rooms. this level opens onto a private terrace, one of three expansive outdoor spaces that wrap the home. additional features include a private service entry, a dedicated 250-square-foot storage unit adjacent to the apartment, and a laundry room. the o'neill building is a full-service condominium offering a 24-hour doorman, concierge, and a 4,000-square-foot common roof deck with an outdoor kitchen. located in the heart of chelsea, the building provides immediate access to the west village and flatiron, as well as many of the city's most established culinary and cultural destinations.