2. John D. Rockefeller Jr.
John D. Rockefeller Jr. gave the United Nations the land to build their New York Headquarters.
Explanation:
The land of UN headquarter was purchased from real estate developer William Zechendorf. The headquarter occupies a site beside the East River with about 17-18 acres.
Zechendorf purchased the land with the intention to create an "X City" on the site. However, Nelson Rockefeller purchased an option for Zechrndorf' waterfront land in Turtle Bay for about $8.5 million (in 1946).
This purchase was funded by Nelson's father, John D. Rockefeller Jr.