By Jared Ebersole in Video 18 Sep 2026

Lantern House and the Art of the Oversized Bay Window

Beside the High Line, Thomas Heatherwick’s Lantern House turns a familiar domestic feature into an architectural illusion, hiding two floors inside one towering bay.

At Lantern House, the windows make counting floors surprisingly difficult. Huge glass bays swell outward from a brick grid, their rounded silhouettes suggesting rooms of extravagant height. Look closer and another arrangement emerges: many of those apparent single windows span two separate floors. The building’s most memorable feature depends partly on making the division between them disappear.

That optical trick gives this Chelsea residence its identity. It also makes an old architectural idea newly conspicuous. A bay window brings the edge of a room outward, opening views at angles that a flat window cannot offer as readily. At Lantern House, that familiar domestic gesture becomes the organizing element of an entire facade.

Where it is

Lantern House

515 West 18th Street, New York, NY 10011

Beside the High Line in Chelsea. Project location

Heatherwick Studio received the commission from Related Companies in 2015 and records the project as completed in 2021. The studio explicitly identifies Victorian and Edwardian bay windows as an inspiration, adapting them into stacked forms framed by substantial brick piers. Heatherwick Studio project account

The appeal of that older arrangement is easy to understand. In an attached house, neighboring buildings constrain opportunities for windows along the sides. Front and rear openings become especially important. A projecting bay gives a room additional glazed faces, allowing someone standing near it to look along a street as well as directly across it.

Its advantage comes from geometry. The central pane faces outward, while the side panes turn toward other portions of the surroundings. Daylight can enter from several angles, and the projection creates an inhabitable edge between room and street. The amount of light still depends on orientation, nearby buildings and the glazing itself. Three faces do not automatically mean three times the daylight.

Lantern House magnifies that relationship between the person inside and the city outside. In the studio’s 2019 announcement, Thomas Heatherwick described a design process that began by considering buildings people would want to live in. Window sills, shades and the smaller components of traditional architecture informed that thinking. The development, comprising towers of 10 and 21 stories connected beneath the High Line, was the studio’s first residential project in the United States. Heatherwick Studio’s project announcement

The facade’s crucial maneuver happens where one floor meets the next. A floor slab would ordinarily interrupt the glazed surface with an obvious horizontal band. Here, shadow-box glazing conceals the floor plate at the spandrel, the opaque portion of the facade at that level. It helps the middle of the bay read as part of the surrounding glass. Facade detail reporting

The result is a deliberate mismatch between the building’s exterior rhythm and its internal divisions. From outside, the eye follows a tall lantern shape. Behind it, the floors remain separate. Double-height describes the visual unit of the facade; it does not necessarily describe the room behind it.

That distinction explains why the windows can feel so large without every apartment needing an enormous vertical void. The design groups ordinary residential levels into a larger composition. Once you spot the concealed division, the building becomes easier to read, but the illusion still holds at a glance.

Producing those shapes required considerable coordination. Facade specialist New Hudson Facades says it engineered more than 3,000 custom window units for the project, with the lantern forms rising over 21 feet. Its team used three-dimensional modeling early in the design process to resolve the relationship between the angled faces, window openings and trim. New Hudson Facades project account

The scale helps explain why the bays look so unusual. A feature associated with individual rooms becomes a repeated object large enough to give the towers their visual rhythm. Each projection changes how the facade catches light and casts shadow. As a viewer moves, the angled surfaces reveal themselves in sequence, making the wall appear deeper and more animated than a flat grid of openings.

The brickwork gives those projections a firm outline. Heatherwick Studio developed a special brick range and incorporated rounded edges and brick soffits, the undersides of projecting surfaces. The material choices refer to Chelsea’s industrial buildings, while the enlarged windows give the development a distinctly contemporary silhouette. Heatherwick Studio’s material description

The High Line makes this treatment especially consequential. Its first public section, between Gansevoort Street and West 20th Street, opened in 2009. The railway had opened in 1934 to carry freight, including meat, dairy and produce. Its conversion into a park introduced a new way to experience the neighborhood: walking above street level, alongside buildings at a height once occupied by trains. Friends of the High Line history

For Lantern House, the park creates an unusual architectural audience. Pedestrians encounter the windows from nearby and from an elevated position. The facade becomes something to pass alongside, with details visible beyond the usual ground-floor shopfront. The same projecting glass that broadens residents’ views also makes the boundary between private rooms and public circulation more noticeable.

The railway structure shapes the entrance, too. A shared glazed lobby connects the two towers beneath the High Line, with the old steel columns passing through the space. Engineering that connection required accommodating movement: a specially developed glazing-head detail allows the suspended lobby structure to move without forcing the glass to follow rigidly. Facade and lobby engineering

Seen together, the lobby and windows reveal a building organized around encounters with its surroundings. The entrance incorporates the infrastructure overhead. The bays push rooms toward the view. And the concealed floor divisions change the scale at which pedestrians perceive the apartments.

On a walk past Lantern House, the revealing detail is halfway up one of those tall glass forms. Find the floor line and the architecture briefly gives away its method. A familiar window has been enlarged, paired and carefully disguised, turning a small domestic pleasure into a building’s public identity.