In the late 1940s with construction completed in the early 1950s, the United Nations core buildings are cutting edge modernism predating Lever Brothers Building and Seagrams Building. But these two buildings get much more play in the architectural history books than the United Nations. Maybe it is because the UN Buildings were the result of a contentious international collaboration. Wallace Harrison was the chief of design, and his firm Harrison and Abramovitz did one of the later buildings. But LeCorbusieur and Neimeyer are generally credited as designers of the major building, the slab office building. Yet the other architects apparently wanted to limit LeCorbu’s influence and visibility. A more interesting designer than Frank Lloyd Wright, perhaps LeCorbu had too much ego and brilliance and the others wanted to knock him a peg. And Neimeyer was seen as too much a follower of LeCorbu.
Regardless, the slab and the assembly hall with curved top are a highly successful symbol of the New York skyline and of the UN. It was edgy when built and it remains edgy.