the building's height and strengthening the superstructure. History Development In 1946, real estate developer William Zeckendorf purchased a site on First Avenue with the intention of creating a development called "X City", but he could not secure funding for the development. At the time, the UN was operating out of a temporary headquarters in Lake Success, New York, although it wished to build a permanent headquarters in the US. Several cities competed to host the UN headquarters before New York City was selected. John D. Rockefeller Jr. paid US$8.5 million for an option on the X City site, and he donated it to the UN in December 1946. The UN accepted this donation, despite the objections of several prominent architects such as Le Corbusier. The UN hired planning director Wallace Harrison, of the firm Harrison & Abramovitz, to lead the headquarters' design. He was assisted by a Board of Design composed of ten architects. Planning The design process for the United Nations headquarters formally began in February 1947. Each architect on the Board of Design devised his own plan for the site, and some architects created several schemes. All the plans had to include at least three buildings: one each for the General Assembly, the Secretariat, and conference rooms. The plans had to comply with several "basic principles"; for example, the Secretariat Building was to be a 40-story tower without setbacks. It would be a freestanding tower surrounded by shorter structures, something which may have been influenced by Le Corbusier's ideals. Early designs called for the Secretariat tower to accommodate 2,300 workers; the architects subsequently considered a 5,265-worker capacity before finalizing the capacity at 4,000 workers. The tower was to be placed at the south end of the complex because it was near 42nd Street, a major crosstown street, and because the underlying bedrock was shallowest at this end. By March 1947, the architects had devised preliminary sketches for the headquarters. The same month, the Board of Design published two alternative designs for a five-building complex, anchored by the Secretariat Building to the south and a pair of 35-story buildings to the north. After much discussion, Harrison decided to select a design based on the proposals of two board members, Oscar Niemeyer and Le Corbusier. Even though the design process was a collaborative effort, Le Corbusier took all the credit, saying the buildings were "100% the architecture and urbanism of