Recognizing the importance of a strong library to support the work of an international organization and to serve as “a centre of international research and an instrument of international understanding,” “Junior” (John D. Rockefeller, Jr.) donated USD 2 million in 1927 for the construction and endowment of the Library of the League of Nations, which became the Library of the UN Office at Geneva in 1946.
Through negotiations by his son Nelson, in 1946 he bought for $8.5 million – from the major New York real estate developer William Zeckendorf – and then donated the land along the East River in Manhattan upon which the United Nations headquarters was built. This was after he had vetoed the family estate at Pocantico as a prospective site for the headquarters.
http://unog.ch/unog/website/library.nsf/%28httpPages%29/EEFB37260D6FC098C1257A720052A6F6?OpenDocument&unid=60249FAB9674BFA0C1256F560035AB55