While the United Nations had dreamed of constructing an independent city for its new world capital, multiple obstacles soon forced the organization to downsize their plans.
They ultimately decided to build on Rockefeller's East River plot, since the land was free and the land's owners were well known.
The diminutive site on the East River necessitated a Rockefeller Center-type vertical complex, thus, it was a given that the Secretariat would be housed in a tall office tower.
During daily meetings from February to June 1947, the collaborative team produced at least 45 designs and variations.
Rather than hold a competition for the design of the facilities for the headquarters, the UN decided to commission a multinational team of leading architects to collaborate on the design.
Harrison was named as Director of Planning, and a Board of Design Consultants was composed of architects, planners and engineers nominated by member governments.
The board consisted of N. D. Bassov of the Soviet Union, Gaston Brunfaut (Belgium), Ernest Cormier (Canada), Le Corbusier (France), Liang Seu-cheng (China), Sven Markelius (Sweden), Oscar Niemeyer (Brazil), Howard Robertson (United Kingdom), G. A. Soilleux (Australia), and Julio Vilamajó (Uruguay).

Niemeyer met with Corbusier at the latter's request shortly after the former arrived in New York City.
Corbusier had already been lobbying hard to promote his own scheme 23, and thus, requested that Niemeyer not submit a design, lest he further confuse the contentious meetings of the Board of Design.
Instead, Corbusier asked the younger architect Niemeyer to assist him with his project.
Niemeyer began to absent himself from the meetings.
Only after Wallace Harrison and Max Abramovitz repeatedly pressed him to participate did Niemeyer agree to submit his own project.
Niemeyer's project 32 was finally chosen, but as opposed to Corbusier's project 23, which consisted of one building containing both the Assembly Hall and the councils in the center of the site (as it was hierarchically the most important building), Niemeyer's plan split the councils from the Assembly Hall, locating the first alongside the river, and the second on the right side of the secretariat.
This would not split the site, but on the contrary, would create a large civic square.

After much discussion, Harrison, who coordinated the meetings, determined that a design based on Niemeyer's project 32 and Le Corbusier's project 23 would be developed for the final project.
Le Corbusier's project 23 consisted of a large block containing both the Assembly Hall and the Council Chambers near the center of the site with the Secretariat tower emerging as a slab from the south.
Niemeyer's plan was closer to that actually constructed, with a distinctive General Assembly building, a long low horizontal block housing the other meeting rooms, and a tall tower for the Secretariat.
The complex as built, however, repositioned Niemeyer's General Assembly building to the north of this tripartite composition.
This plan included a public plaza as well.
The UN headquarters was originally proposed alongside a grand boulevard leading eastward from Third Avenue or Lexington Avenue, between 46th Street to the south and 49th Street to the north.
These plans were eventually downsized into Dag Hammarskjöld Plaza, a small plaza on the south side of 47th Street east of Second Avenue.

Wallace Harrison's assistant, architect George Dudley, later stated: "It literally took our breath away to see the simple plane of the site kept open from First Avenue to the River, only three structures on it, standing free, a fourth lying low behind them along the river’s edge...[Niemeyer] also said, ‘beauty will come from the buildings being in the right space!’.
The comparison between Le Corbusier's heavy block and Niemeyer's startling, elegantly articulated composition seemed to me to be in everyone's mind..." Later on, Corbusier came once again to Niemeyer and asked him to reposition the Assembly Hall back to the center of the site.
Such modification would destroy Niemeyer’s plans
While the United Nations had dreamed of constructing an independent city for its new world capital, multiple obstacles soon forced the organization to downsize their plans. They ultimately decided to build on Rockefeller's East River plot, since the land was free and the land's owners were well known. The diminutive site on the East River necessitated a Rockefeller Center-type vertical complex, thus, it was a given that the Secretariat would be housed in a tall office tower. During daily meetings from February to June 1947, the collaborative team produced at least 45 designs and variations. Rather than hold a competition for the design of the facilities for the headquarters, the UN decided to commission a multinational team of leading architects to collaborate on the design. Harrison was named as Director of Planning, and a Board of Design Consultants was composed of architects, planners and engineers nominated by member governments. The board consisted of N. D. Bassov of the Soviet Union, Gaston Brunfaut (Belgium), Ernest Cormier (Canada), Le Corbusier (France), Liang Seu-cheng (China), Sven Markelius (Sweden), Oscar Niemeyer (Brazil), Howard Robertson (United Kingdom), G. A. Soilleux (Australia), and Julio Vilamajó (Uruguay).
Niemeyer met with Corbusier at the latter's request shortly after the former arrived in New York City. Corbusier had already been lobbying hard to promote his own scheme 23, and thus, requested that Niemeyer not submit a design, lest he further confuse the contentious meetings of the Board of Design. Instead, Corbusier asked the younger architect Niemeyer to assist him with his project. Niemeyer began to absent himself from the meetings. Only after Wallace Harrison and Max Abramovitz repeatedly pressed him to participate did Niemeyer agree to submit his own project. Niemeyer's project 32 was finally chosen, but as opposed to Corbusier's project 23, which consisted of one building containing both the Assembly Hall and the councils in the center of the site (as it was hierarchically the most important building), Niemeyer's plan split the councils from the Assembly Hall, locating the first alongside the river, and the second on the right side of the secretariat. This would not split the site, but on the contrary, would create a large civic square.
After much discussion, Harrison, who coordinated the meetings, determined that a design based on Niemeyer's project 32 and Le Corbusier's project 23 would be developed for the final project. Le Corbusier's project 23 consisted of a large block containing both the Assembly Hall and the Council Chambers near the center of the site with the Secretariat tower emerging as a slab from the south. Niemeyer's plan was closer to that actually constructed, with a distinctive General Assembly building, a long low horizontal block housing the other meeting rooms, and a tall tower for the Secretariat. The complex as built, however, repositioned Niemeyer's General Assembly building to the north of this tripartite composition. This plan included a public plaza as well. The UN headquarters was originally proposed alongside a grand boulevard leading eastward from Third Avenue or Lexington Avenue, between 46th Street to the south and 49th Street to the north. These plans were eventually downsized into Dag Hammarskjöld Plaza, a small plaza on the south side of 47th Street east of Second Avenue.
Wallace Harrison's assistant, architect George Dudley, later stated: "It literally took our breath away to see the simple plane of the site kept open from First Avenue to the River, only three structures on it, standing free, a fourth lying low behind them along the river’s edge...[Niemeyer] also said, ‘beauty will come from the buildings being in the right space!’. The comparison between Le Corbusier's heavy block and Niemeyer's startling, elegantly articulated composition seemed to me to be in everyone's mind..." Later on, Corbusier came once again to Niemeyer and asked him to reposition the Assembly Hall back to the center of the site. Such modification would destroy Niemeyer’s plans
Headquarters of the United Nations