Can We Learn From Our Past Treatment of Mother Nature? - The River (1937) and The Plow That Broke the Plains (1937)
Link
http://hines.blogspot.com/2012/01/river-1937-youtube.html
If a picture is worth a 1000 words, a movie must be worth 1,000,000 words... two movies --> 2,000,000 words...
The River was written and directed by Pare Lorentz and, like Lorentz's earlier documentary The Plow That Broke the Plains, was also selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant", going into the registry in 1990.
The film won the "best documentary" category at the 1938 Venice International Film Festival.
If you have not seen both, they are well worth your time.
Regards,
Monte Hines