The design of architect Fumihiko Maki’s World Trade Center Tower 4 has two main functions: to uphold the WTC master plan created by Daniel Libeskind -- which calls for each of the towers to form a sort of descending spiral that sends attention down to the Memorial plaza -- and to both complement its neighboring towers and complete the spiral through a distinct, distinguished design.

Maki’s tower accomplishes both tasks simply and elegantly through its minimalist, angular shape. The tower’s four corners each rise to varying topographical elevations. Most notable among these is a significant setback on its western façade that creates the image of a single step. The tower is clad in glass, and some large sections sandwich perforated meshed metal -- an effect that provides shading on the interior and a transparent, reflective quality on the exterior.

The result of these innovations is a sleek, slender silhouette with obtuse angles that appears highly geometric, but whose “skin” appears more organic by actively changing with the light of day.

The innovative design of Tower 4, located at 150 Greenwich Street (the southwest corner of the site), was unveiled on September 8, 2006, by former Governor George Pataki, former Deputy Mayor Dan Doctoroff, developer Larry Silverstein, and other rebuilding officials.

Reaching a height of 64 stories (975 feet), the tower will house 1.8 million square feet of office and 146,000 square feet of retail space. It will feature 53 office floors, five stories of retail, and access to underground transit. Two-thirds of the tower will be occupied by the Port Authority of New York and New Jersey and the City of New York, and the remaining space will be retained by Silverstein Properties for commercial tenants.

Like each of the WTC towers that Silverstein Properties is building, Tower 4 will consist of a central concrete core, made of steel encased in reinforced concrete. It also will feature life-safety systems that exceed New York City building code and Port Authority requirements.

In designing the building, the tower’s architects sought to achieve the gold standard under the Leadership in Energy and Environmental Design (LEED) by the U.S. Green Building Council, the highest energy efficiency rating.

The tower’s office lobby, with a 47-foot ceiling height, will have entrances on Greenwich, Cortlandt, and Liberty Streets, and a panoramic view of the memorial plaza. The retail entrances also will give commuters access to the WTC Transportation Hub and New York City Transit.

Construction of Tower 4 began in summer 2008, upon the Port Authority’s completion of the WTC’s “east bathtub,” located between Church Street and the future restored Greenwich Street. Developer Silverstein Properties expects to complete the building in 2012.

Click here to view a slide show of Tower 4, 150 Greenwich Street.
Click here to see the latest information on WTC Tower 4 construction.