In response to requests from the United Nations, New York City and the State of New York combined to create a special public corporation and development zone to provide phased expansion space for the United Nations. The program and site were analyzed which resulted in a master plan consisting of three buildings; two forty story towers connected by a common base and a third building of fifteen stories to serve as headquarters for UNICEF.

One of the forty-story towers was the first phase of the master plan to be constructed, followed by the second tower in Phase II. These two buildings contain office spaces, meeting rooms, a hotel, restaurant, and a health club for a total area of 925,000 square feet. A single hotel lobby serves both towers while each office portion has a separate entrance.

The reflective insulating glass cladding of the towers is a uniform grid which accommodates both the office and hotel floor heights and emphasizes the strong minimalist structural form of the buildings. The towers' shape is derived, in part, from the variations in use and the desire to establish a strong relationship with the adjacent low-rise buildings and the United Nations Secretariat.

The headquarters of UNICEF included residential apartments in upper floors, which have recently been converted to office spaces as there was a need for expansion. The Ground Floor contains lobbies, employee dining rooms, a retail shop, and a large exhibition space which opens onto a small public park. The building's structure is clad with bands of pink and green granite with windows of the same green reflective glass used for the Phase I and II towers. A twenty-foot high colonnade runs the full length of the site and knits the park and base of the building together. Tables, chairs, benches, trees, a stone wall and waterfall provide a quiet, relaxing atmosphere in Midtown Manhattan.

Programming, master planning, zoning analysis, governmental approvals, full architectural services for the three buildings were completed as scheduled.

Renovations and upgrades at UN Plaza are currently ongoing.