Yesterday’s “Map of the Day” from National Geographic came from the UI Libraries.
http://ngm.nationalgeographic.com/map/map-day
The map is from the Official Guide Book of the New York’s World Fair, 1939. The Special Collections department also has a small World’s Fair Collection (MsC840) with materials such as guidebooks and catalogs from 1893-2005 (including other materials from the 1939 New York World’s Fair), and with postcards from as early as the 1850s.