Much of the progress at the World Trade Center has, in fact, taken place at or beneath the surface, and the first portion – a Memorial Plaza – is scheduled to open later this year. We created a guide to the nine programmatic elements under construction:

Office Towers
The construction of five new towers will drastically alter Lower Manhattan’s skyline, adding over 10 million square feet of office space.

The tallest and most notable of the towers is One World Trade Center, formerly called the Freedom Tower. It will rise 1,776′ to become America’s tallest building. The structure was designed by David M. Childs of Skidmore, Owings & Merrill (SOM). Its crystalline form extends from a 200′-tall concrete base with chamfered edges. The structure’s cladding, glazed insulated panels, will span floor to floor without the aid of an intermediate mullion – a first in skyscraper construction. The program will include office space, an observation deck, restaurants, and broadcast facilities and antennae. Steel has been erected to the 62nd floor, and the glass curtain wall has been installed up to the 28th floor. One World Trade Center is expected to be completed in 2013.


Images 1, 2, and 3 are courtesy of Skidmore, Owings & Merrill LLP. Image 4 is courtesy of Skidmore, Owings & Merrill LLP/by-encore. Image 5 is courtesy of Skidmore, Owings & Merrill LLP/dbox Studio. Images 6 and 7 are courtesy of Skidmore, Owings & Merrill LLP/Seventh Art Group.
Located at 175 Greenwich Street, Tower 3 has been designed by Richard Rogers of Rogers Stirk Harbour + Partners. It will feature distinctive, diamond-patterned bracing and a stepped profile capped with antennae. The 80-story tower will contain office space, including five trading floors, as well as several levels of retail. Like Tower 2, foundation work began last summer and Tower 3 has since reached grade.

Tower 4, or 150 Greenwich Street, was designed by Maki and Associates and will rise 72 stories. Like the other towers, it will contain mostly office space, including the headquarters for the Port Authority of New York and New Jersey (PANYNJ), and some retail. The floor plate of the tower shifts from a parallelogram, a reflection of the shape of the World Trade Center site itself, to a trapezoid on upper floors. The minimal design features coated glass that will shift in perception, depending on atmospheric conditions. A large interior atrium will provide views of the Transportation Hub. Currently, the structural steel erection is in progress, and Tower 4 is projected to open in the fall of 2013.


- View from Memorial Park and Liberty Street
- Site Model
- Ground Floor Plan
- View of office lobby from Memorial Park
- Typical Office Plans: Low, Mid-Rise Floor Plan
- Typical Office Plans: Low, Mid-Rise Floor Plan
- Typical Office Plans: High-Rise Floor Plan
Tower 5 will be located on the south side of the site, an area formerly occupied by the Deutsche Bank Building, which was irreparably damaged in the attacks. Kohn Pederson Fox created a design for an office tower that would serve as the headquarters for JP Morgan Chase, with trading floors dramatically cantilevering outward. However, the company chose to relocate elsewhere, and now the building will be developed by the PANYNJ. The demolition of the Deutsche Bank Building was recently completed, and work has begun on Tower 5.
Transportation Hub
The World Trade Center Transportation Hub designed by Santiago Calatrava will rival Grand Central Station in size, serving over 200,000 commuters daily. Calatrava compared the form to a bird being released from a child’s hand. Originally, the roof was designed to retract for added light and ventilation, but this feature was eliminated d
ue to budget restraints. Construction crews have begun installing a Vierendeel Truss that will support the roof, and they have excavated and poured slabs at many levels below grade. The Transportation Hub is scheduled to open mid-2014.
Performing Arts Center
A new performing arts center designed by Frank Gehry will bring culture into the mix of Lower Manhattan. It will become the permanent home for the Joyce Theater, a modern dance company, and will also host the Tribeca Film Festival. The project is still in the planning stages but is said to include a 1,000-seat performing arts center and a second stage, rehearsal space, classrooms, and a cafe. Construction has been delayed due to lack of funding, but in October 2010, the Lower Manhattan Development Corporation board voted to allocate $100 million to develop the performing arts center.
Memorial Plaza
At the center of the site, an 8-acre park has been designed by Michael Arad and Peter Walker. Two reflection pools with cascading waterfalls have been sunk within the original footprints of the two former World Trade Center towers. Bronze parapets will be inscribed with the names of victims of the attacks. Over 150 of 400 Swamp White Oak trees have already been planted along the plaza, which will also feature grasses and mosses, flowering ground covers, and cobblestone pavers. The plaza will open on September 11, 2011 to commemorate the 10th anniversary of the attacks.
9/11 Memorial Museum
A metal and glass-clad entry pavilion on the plaza designed by Snøhetta will lead visitors to the 9/11 Memorial Museum below grade, and the pavilion will also showcase the “tridents,” two large steel columns salvaged from the original World Trade Center towers. Steel installation for the pavilion is complete and cladding is in progress. The 9/11 Memorial Museum itself is situated among the former foundations of the twin towers, and visitors will make the descent from plaza level all the way down to bedrock. Steven Davis, FAIA, Partner, Davis Brody Bond Aedas – the firm that designed the 9/11 Memorial Museum – explains the sequence and design process:

People will engage the site from different perspectives, both emotionally and physically. Some will come for a pilgrimage; others will come for a brief lunch break from work. The sloping procession begins at the plaza, and visitors arrive in Memorial Hall, which is essentially an information and orientation space. At this point, you haven’t yet engaged with the enormous scale of the Museum, which is then revealed at the West Overlook and the first siting of the slurry wall. You see the slurry wall from a distance, and you’re not really sure what it is, and then it strikes you that this is where it all took place. [Also located in this space is the “Last Column" from the twin towers, which was covered in tributes from workers, rescuers, and family members of victims.]
Next, you proceed along from the West Chamber down the ramp to the East Overlook, at which point you are suspended 25 feet in the air between where the two towers stood. Then you descend by stair or escalator down to bedrock. The major exhibits will be located within the towers’ footprints. Experiencing this w
hole sequence could take 15 minutes or less, but more likely, an in-depth visit could take a couple of hours. When it’s time to leave, you ascend to Memorial Hall on an escalator. We’ve consciously separated visitors who have experienced the Museum from those who have not yet experienced it.
The concept for the spatial consequence of the Museum is based on the fact that we have not intervened in terms of the scale or the authenticity of the spaces. We inherited a series of program elements for this project: bedrock serves as the floor, the slurry wall defines the west enclosure, the Memorial Plaza is the roof, and the PATH station forms the east enclosure. We’ve done nothing to reduce the impact of the rawness of these spaces; in fact, we’ve tried to optimize the impression of scale. We don’t want to bias any of the events, and we don’t want to be overly influential in terms of emotion and context — we’re allowing it to reveal itself.
A traditional museum is an icon which houses exhibits, but this museum is the inverse — it is, in fact, an exhibit, which the icon. We learned a new way of thinking about museums and how to communicate and provide information. Interestingly, we are at the site of the atrocity, which is, of course, the most significant thing about the Memorial Museum; it is unlike the Vietnam Memorial in Washington, DC, and the Memorial to the Murdered Jews of Europe in Berlin, which are removed.
The construction of the below-grade Museum is quickly progressing, and it will open on the 11th anniversary of the attacks, September 11, 2012.