Gracias Amigos was a 1944 propaganda short produced by the Office of the Coordinator of Inter-American Affairs to educate the American public about the contributions of Latin America during World War II.
The short begins by describing the "island" of the United States, how self-sufficient it thought it was, and how it felt that the rise of the Axis powers wouldn't affect it.
The film shows the many vital uses these resources are put to, including rubber and quinine.
The mobilization of the Latin America armies in anticipation of any Axis threat is discussed, as well as the clearing out of subversion and submarine watches.
But most important, in the eyes of the film, is the base at Naha, Brazil, which was used to quickly transport military supplies from the US or Latin America, over the Atlantic, to Africa, and thence to the British armies in Egypt.