A pre-war Park Avenue apartment in New York posed a classic design challenge — how to preserve character while transforming it for modern family life. This gut renovation centers on a long entry hall reimagined as a millwork “spine” that organizes the layout and conceals seating, a hidden bar, backlit wine wall, and sleek storage. The new plan adds a bedroom, bath, laundry, and 31 feet of closets. A blackened steel fireplace and art deco powder room complete this warm, tailored, and unexpectedly fun home.