Why the Oculus Roof Opens Only on September 11 at the World Trade Center

A $4 billion roof over hallowed ground

The OculusPATH TrainThe separate rapid transit system linking Manhattan with Hoboken, Jersey City and Newark under the Hudson. opened on March 3, 2016, at the World Trade Center, and its price tag, around $4 billion, made it the most expensive train station ever built. Santiago Calatrava's design is a working transit hub, and its most argued-over feature sits overhead: a 330-foot skylight running along the spine of the roof.

The architect's original proposal was more ambitious than what stands there. The entire roof would retract, opening the hall to the sky. Engineering and budget reviews cut that down over the years until only the skylight along the roof spine remained operable. For most of the year it stays closed, and the hall runs on electric light and on the pale ribs of Calatrava's structure. Commuters pass through it every day of the year, which makes the once-a-year exception easy to miss.

The one day it opens

On September 11, the skylight opens and a beam of sunlight drops into the hall.

That single annual movement is where the building stops being a design story and becomes a memorial one. The Oculus stands on the ground of the World Trade Center, beside the 9/11 Memorial9/11 Memorial & MuseumThe memorial pools and underground museum at the World Trade Center site documenting the September 11 attacks., whose pools trace the footprints of the towers. The roof opens on the date the site lost those towers. The reason is not decorative, it is written into the ground the station stands on.

Seen from inside, the comparison to an eye is hard to avoid, the skylight is the pupil, the ribs are the lids, and the operable skylight is the only part of that geometry that still moves on command. The whole roof was never going to retract. What survived of the idea is a line of daylight, timed to the anniversary.

How to see it

The Oculus is open daily and free to walk through, it is a station, not a ticketed attraction. Stand under the middle of the hall, directly beneath the skylight line, and look up along the spine, that is where the beamTop of the RockRockefeller Center's observation decks, prized for the head-on view of the Empire State Building and Central Park. reads most clearly when it opens.

On September 11, the opening is tied to the anniversary, so confirm the year's timing with the official World Trade Center and Port Authority pages rather than guessing. Arrive early, since crowds around the memorial plaza are heaviest that morning.

The station and the 9/11 Memorial sit side by side, a couple of minutes apart on foot, the memorial pools on the plaza are free to visit, while museum tickets are separate. From there, Wall Street is a short walk west, and the Brooklyn BridgeBrooklyn BridgeThe 1883 Gothic-towered suspension bridge whose elevated walkway is the city's most famous free walk. is a walk or one subway stop away.

A guided walking tour of the World Trade Center and memorial grounds strings the Oculus, the pools and the surrounding streets into one route of about two hours, from $35 (estimated), traveler reviews on the activity page are the quickest way to judge whether the pace suits.

More on the place itself: 9 11 memorial.