The Gentle Giants / Ancient Diseases / Water Weeds The Nature of Things : Season 23 Episode 14

The Gentle Giants: A film on the gray whales who live off the pacific coast of North America. Ancient Diseases: A look at paleopathology and what can be learned about the past of man and the history of diseases through the autopsy of ancient human remains. Water Weeds: A look at an experimental project in Listowel, Ontario, using cattails to purify sewage. The cattails thrive in sewage where they also filter out some industrial contaminants as well as deal with organic compounds.