A number of unusual scientific phenomena around the world raise serious questions about the planet's ecological balance in this four-part documentary produced by National Geographic. National Geographic: Strange Days on Planet Earth offers both fascinating and disquieting information on how and why certain species are showing up in places where they've never been before, the short- and long-term effects of a slight rise in the global temperature, how the elimination of certain predatory animals may be causing as much harm as good, and an investigation of how effective measures to clean our drinking water have been. National Geographic: Strange Days on Planet Earth features narration by actor Edward Norton. ~ Mark Deming, Rovi