20 East End Avenue's breathtaking Maisonette, a prized residence designed by the world- renowned architect Robert A.M. Stern, spans approximately 4737 interior square feet, over three floors. Designed in the style of classic pre-war apartment houses, this palatial home features soaring ceilings, expansive casement windows, custom designed moldings, and Appalachian oak flooring with a walnut stain. The Maisonette offers a gracious entry gallery with a grand staircase that connects entertaining and living spaces to the home's private quarters above. This residence is washed with natural light throughout and features a substantial chef's kitchen with Gaggenau 400 series appliances and millwork custom designed by Stern, a spacious formal dining room, a majestic living room, and a library designed to easily function as a fifth bedroom. The expansive master suite features sweeping views of East End Avenue and the East River, a gracious master bathroom and a separate dressing room with two large walk-in closets. Three generously sized bedrooms, all with en-suite baths complete the second level. The lower level features a large utility room with a washer, dryer and sink. The building's luxurious library with adjoining billiards, card and bar rooms, is located just a short hallway off the upper level foyer essentially making it an extension of the apartment. Thefully equipped fitness center, a spa featuring sauna, steam and private treatment room, and a teen arcade can be accessed off of the lower level. The building also features a gated port cochere for residents and guests.