The Headquarters of the World Organization is located on an 18-acre site on the East side of Manhattan. It is an international zone belonging to all Member States. The United Nations has its own security force, fire department and postal administration.
The Headquarters consist of four main buildings: the General Assembly building, the Conference Building, the 39-floor Secretariat building, and the Dag Hammarskjold Library, which was added in 1961. The complex was designed by an international team of 11 architects, led by Wallace K. Harrison from the United States, with the final proposal being a combination between Oscar Niemeyer and Le Corbusier's designs.
The Secretariet Building
Niemeyer's slender Secretariat Building has become the iconic symbol of the United Nations; the slender office tower's green glass and Vermont Marble shimmer in the sunlight and the water of the East River that while even though permanent in structure appears as an ever changing entity that is constantly adapting to the atmospheric conditions and the surrounding context. It's modern, International Style aesthetic was an intentional decision by Niemeyer and the rest of the collaborating architects as a way in which to symbolize change that embodies a sense of "newness" that sheds light on the optimistic future of the world's nations working together as one collective body rather than the disparate warring units of the past.
The General Assembly Hall
The General Assembly Hall is the largest room in the United Nations, with seating capacity for over 1,800 people. The design of the room was a collaborative effort, however the concrete chamber was based on Le Corbusier's design (scheme 23). Le Corbusier's heavy, concrete General Assembly building is the heart of the United Nations diplomatic enforcement. The low statured building has an iconic dome atop a concavely compressed volume that houses the various departments' assembly halls. In contrast with Niemeyer's tower, Corbusier's hall internalizes all of its functions creating a heavy, masked quality, which evokes a monolithic and powerful stance within the city and the UN complex. The circular space creates a strong sense of inclusion that wraps the seated diplomats around the podium and the Secretary General's desk. To emphasize the international character of the room it contains no gift from any Member State.